"The Road Not Taken" is the 26th episode of the 29th series of Casualty. It was preceded by "Toxic Relationships" and followed by "Something Borrowed, Something Blue". Zoe Hanna was the centric character in this episode. Former regular Maggie Coldwell made a guest appearance in this episode. The events of the episode were non-canon.
After spending the night in a hotel with Max, Zoe realises that she is going to be late for work. She arrives and gets a message from Maggie asking if she wants to join the air ambulance. Zoe then has to decide whether to tend to a pregnant women or a young girl who has been run over. Zoe chooses the young girl as she is in more danger, however she ends up dying. The pregnant mother leaves the hospital but after more pain her partner brings her back in only for them to have a massive crash on the way in. Zoe then has to choose whether or not to do a risky procedure called a reboa that could save the mother's life, or to do a perimortem cesarean that she has also never done before but would save the baby. She opts for the Reboa in hopes of saving them both. She successfully inserts it just as Mr. Thompson from Obstetrics and Gynaecology arrives. However he refuses to do the C-Section in the ED as he doesn't have the right tools or staff, So takes them up to his ward. Zoe later goes to check on them only to find the baby died but the mother is alive.
Zoe then relives the day to see if she can come out with a better outcome. She takes the option of seeing the pregnant lady first, but tells her to go home as she doesn't seem to be in any imediate danger. She then goes to see the little girl when the ambulance arrives, but she is already dead as there was no CPR done at the scene for at least 5 minutes. After sending the pregnant lady home she crashes and Zoe is faced with decision again whether to do the reboa or the C-section. This time she opts for the perimortem C-section and is able to save the babies life after reviving her. However when she goes to check on the mother on Mr. Thompsons ward she is informed that the mother has died.
Zoe relives her day for a third and final time. She gets up early and makes her way to the shop. The ambulance containing the young 6 year old girl goes by and Zoe is able to save her on board. She arrives in the ED and Tess tells her that a mother is being transferred to maternity.