Holby Wiki - Casualty and Holby City

MacKenzie "Big Mac" Chalker, better known to his friends and colleagues simply as Mac, is a former health care assistant who worked at Holby City Hospital's emergency department from 2007 until 2016. He was initially a porter upon his arrival in the department in November 2007 but later trained to become an emergency care assistant for extra money in 2013. In 2014, he retrained to become a health care assistant and work back in the ED following Jeff Collier's death. In 2016, he resigned following an incident with some stolen drugs which left him feeling guilty.

Early life

Big Mac was born to a shy, and deaf, mother and a father who left him when he was 5 years old. As a result, Big Mac's mother smothered him, giving him what he wanted and this made him lazy. He eventually joined the army as a veteran of the Falklands War of 1982, where many of his fellow soldiers were killed while he survived. He eventually became a cook instead, but the fear of being shot took over and he deserted. He went back home to his mother who was diagnosed cancer and Mac spent a lot of time in hospitals due to this. This also made Mac become a hypochondriac as if his mother had taken her symptoms seriously, she may have still been alive.

Time in the emergency department (2007-16)

Mac started working as a porter in Holby City ED in November 2007. On his first day, he was revealed to be a computer whiz, and he traced the creator of the Toxic Shark blog that was describing events happening in the ED. A couple of weeks later, Mac failed to clean up a puddle on the floor which Adam later slipped on. He attributed this to his bad back, and also told the rest of the staff that he wouldn't be able to push patients who weighed over 15 stone. By December, Mac had built friendships within the ED, particularly with the nursing staff whom he shared a new years celebration with in the staff room. However, Tess soon stormed in and sent them all back to work.

In January 2008, Big Mac found and carried Tess into resus after she was injected with an unknown substance by new nurse Lewis. After she was able to tell them who was responsible, the hospital was sealed off, and Big Mac was eventually able to apprehend Lewis. Lewis told them that he only did it because Tess took him out of resus due to his lack of experience, and that he wanted to be there saving lives. In March, Mac set up a fake profile in order to get a date with staff nurse Kelsey Phillips, but ultimately stood her up due to nerves.

In June 2010, Mac was supposedly cursed by a woman named Grace. Petrified, he later got a blood test, MRI and urine samples done, and eventually Noel and Jay took advantage of him by telling him the only way he could remove the curse was to draw around the whole hospital in chalk, which he did.

In January 2012 following renovations of the ED as a result of the fire, Mac managed to catch a young boy when his father accidentally dropped him off of a balcony outside the ED. He was praised for his heroic actions by everyone. During the Holby riots that July, Mac took care of a young boy found on the streets and Linda's niece and nephew whilst chaos descended upon the ED.

In September, Mac was left feeling isolated from his friends after having an argument with Louise. Later in the day, his old friend Snapper came into the ED after being injured in a strong storm in Holby. He initially refused surgery so Linda asked Mac to try to persuade him to sign the consent form. He was successful but later horrified when Snapper died and he couldn't help but blame himself. He later went to retreat to the store cupboard for some time alone but suffered a heart attack in there. Louise found him on the floor and alerted the medics and he was rushed into resus and saved. He returned to work in mid October despite protests from both Noel and Louise, however he was able to help a patient in need but soon found his good intentions questioned by Dylan.

In March 2013, Mac took part in a half marathon in Holby, and seemingly met the women of his dreams. However, when she mistook him for a doctor he failed to correct her which led to her walking away when she found out the truth about his career. In July, Louise once again grew angry with Big Mac when he took pity on a homeless man.

In October, Mac successfully helped a man overcome his claustrophobia which led Louise to encourage him to apply for the vacant position of an emergency care assistant. The following week, Louise applied in Mac's name anyway which left him angry, but he soon found out that he had been successful in the application. He had his first shift as an emergency care assistant in early December, and on his first day helped treat two brothers who had driven into a concrete block.

Iain with an injured Mac, whilst Kenny holds them hostage.

In March 2014, Iain and Big Mac were called out to a fire at a local B&B, but Iain realised that the casualty was Beth Archer, the wife of one of Iain's old army colleagues. When her husband Kenny became suspicious that they were having an affair, he went to the ambulance station in search of him. He found Mac there, and accidentally gave him a deep head laceration when he pushed him onto some oxygen cannisters. Eventually the police arrived, and Kenny believed Iain. Mac was admitted to the ED as a patient and Kenny was arrested. In November, Mac attended a war memorial service, but was still struggling to cope with Jeff's death and requested a transfer back to the ED. He was later appointed the position of healthcare assistant in order to assist the nursing team.

By the end of January 2015, Mac had settled into his new job in the ED, but also encountered some money troubles. This led him to a pawn shop where he planned to sell some of his possessions for some extra cash, but whilst there he encountered a window cleaner who had been stabbed in the leg. Once at the hospital, Mac discovered that he wasn't the only one with money troubles as the window cleaner was on his way to deliver debt money to his aggressive brother. The following week, Honey became concerned when she caught Mac stealing stock from the food bank which Robyn had set up weeks earlier in an attempt to be more helpful.

In June, Mac found a talisman in the road which he believed saved his life after narrowly avoiding being crushed by a falling electrical box. Dylan went on to possess it and as a result it contributed towards his OCD. In August, Dixie and Big Mac worked together to help an elderly female couple get married, fifty years after their engagement. At Zoe and Max's wedding, Noel and Big Mac accidentally hired prostitutes as dates, leaving Ethan to pay the bill.

In September 2015 during a terrorist infiltration of the ED, Big Mac was taken hostage by the terrorists and asked to film them making Denise Ellisson read a note before they would kill her. However, the police arrived and rescued him along with Jacob and Connie who had already entered the room inadvertently.

Big Mac aids with the cleanup of reception after and incident during the black alert.

In January 2016 in the morning after a night shift, Noel was attacked whilst walking home through the park with Big Mac. The attacker, Mercedes Christie, was attempting to pay off her debt and saw Noel on his phone and tried to take it. However, things soon got out of hand and Noel was left unconscious and seriously injured. Meanwhile, Big Mac cowardly hid in the toilets. Back at the ED, Noel was treated but Big Mac had frequent encounters with the attacker when she arrived at the ED. Eventually, Big Mac paid her the money she wanted, £70, so that she wouldn't expose him to his colleagues as a coward. Noel was left under the impression that Big Mac had been a hero and saved him.

In February Noel returned to work, desperate to give Mac the recognition he deserved and even contacted the media to see if they'd be interested in covering the story. The article got published the following week, and his guilt began to overwhelm him when he was regarded as a hero by the press. Later in February, Mercedes returned to the ED after having fallen during a police chase an injuring her abdomen. He soon began to sympathise with her situation and she begged him not to tell the police despite his concerns to her about lying to Noel. However Kate Wilkinson, the police officer who investigated the attack, spoke to Big Mac when she thought he was acting strange around Mercedes. Eventually she revealed to him that they had found Mercedes' DNA at the scene of the attack and therefore made the connection between them. The police then revealed the truth to Noel, and he told Mac he was moving out due to the fact he had lied.

In March, Jack and Louise locked Noel and Big Mac in the storage cupboard together until they could resolve their differences. Despite initially arguing, they eventually came to terms with one another and Noel forgave Mac. However, Big Mac had frequently visited Zoe in search of repeat prescriptions for painkillers which were initially prescribed for him following his bad back sustained during Noel's attack. Zoe eventually told Mac that he wouldn't need them anymore and to go and see his GP, but he became dependant on them. He later helped Robyn unpack the drugs delivery but when some were dropped on the floor, he took the opportunity to pocket a few.

Mac admits that he was the one who stole the pills to Noel.

In April, Mac gave Mercedes some drugs he got from the pharmacy after he volunteered to pick up some prescription medication. She told him to give her some and that they could help each other out, but he was reluctant to have any further involvement in supplying her with drugs. Later in the month, Charlie and Rita started to become suspicious when they discovered that the amount of tramadol they were getting in from the pharmacy didn't match the amount which was being given to patients. As a result, Mac told Mercedes after she turned up at the ED wanting more that he would be unable to. She threatened to reveal his secret to everyone if he didn't so he ordered some more tramadol from the pharmacy but was unable to pick them up when interrupted by a suspicious Charlie. After the shift, Mac confided in Noel about his addiction and the fact he was the one taking the drugs from the stock. They told Mercedes that she should leave him be, as she didn't want another court case in additon to the mugging one. Noel set Mac up with a chance to go to an NA meeting, but he turned away just before walking in.

The following month, Noel inquired about how Mac's NA meetings were going and he lied and told Noel they were going well despite having never been to one. Later in May, Mac had finally started to manage his addiction and stopped taking the pills. However, after a stressful day he relapsed and stole a packet from a woman's handbag who had gone to the ED to visit her husband. He took the pills, and was almost caught by a young boy but he shouted at him causing him to run away. Later in the day, Charlie found Mac in the storage cupboard and Mac finally decided they could talk about it. Charlie spoke with him in the office and Mac explained everything, and that he was the one who had stolen the pills. Charlie was shocked, but promised to put the drugs somewhere safe, and later put them in his own locker. After their shift, Charlie accompanied him to the NA meeting, and Mac finally introduced himself and admitted his problem.

The next week, Hanssen urged Connie to see the severity of the situation after the patient's relative who had the pills stolen the previous week had gone to the press. He later spoke to Elle and told her that the trust were looking for someone to blame and that Connie's job could be in danger. Elle later found the pills in Charlie's locker and went straight to Rita who went to Connie straight after. Despite Elle's inquiry as to whether Connie would go to Hanssen in an attempt to help her, Connie told Elle to leave it to her, and later told her to leave the room. Elle later inadvertently revealed to Hanssen that Charlie was responsible thinking that he already knew. After Charlie was suspended, Big Mac was left feeling guilty at the fact it was actually his fault.

Big Mac prepares to ride away on his motorcycle after saying goodbye to his colleagues.

A week later, Mac felt pressured by Noel to tell the truth, as Noel secretly had suspicions that Mac was the one who had stolen the drugs from the patient. Mac set up a camera in the staff room in an attempt to make it look like he was attempting to catch the thief, but the only significant thing that'd been noticed was a patient taking the Vitamin C pills he'd left on the side. After a stressful day where he found himself in trouble more than once, he eventually decided to come clean to Rita and tell her that he was the one who stole the drugs. Although she said he wouldn't need to resign, he chose to anyway and later apologised to Charlie at his NA meeting after leaving the ED.

Charlie's anniversary (2016)

Big Mac in his video message in 2016.

Just a two months after his departure, he recorded a video message for Charlie to congratulate him on his 30th anniversary of working at the hospital. He labelled Charlie as a guardian angel.

Personal life

Big Mac lives on the Farmead Estate, an estate full of thugs and gangs of youths. Here, he has become a vigilante, protecting the less capable people of the estate.

When Jessica Harrison moved onto the estate, Mac helped her out with a lot of things. Jessica saw a different side to Mac. He was scared of the gangs and violence, as he was in the war. He just let them do what they wanted, including trashing his flat.


  • His mother died of a long drawn out cancer.
  • He fought for Tess' rights when they tried to make her a scapegoat.
  • He had a crush on Kelsey, but nothing ever came of it.
  • He hates being called 'Apple Mac'.

Behind the scenes

Charles Dale portrayed Big Mac for just under 9 years on Casualty through 9 series.

Big Mac was portrayed by Charles Dale on Casualty from 2007 to 2016. With the departure of Dixie in January 2016, Dale became the second longest serving cast member until his departure in June. In April 2016, Dale hinted over Twitter that he was leaving the show, although this remained unconfirmed until June, when his departure was announced by online articles. His final episode, "You Make Me Sick", aired on 11 June 2016. He made a brief appearance in the 30th anniversary special episode at the start of series 31 two months later.


See also: Character appearances and Category:Big Mac centric.

Big Mac made his first appearance in the series 22 episode "How Soon Is Now" and his final appearance in the series 30 episode "You Make Me Sick". Overall, he had 0 centric episodes.