On 8 September 2007, Nell and Denny Davidson planned to attack an animal testing facility with a peroxide bomb. However, the bomb exploded as it was loaded onto a coach on Hesketh Road, resulting in dozens of casualties and a neighbouring shop partially collapsing. Nell, who had sustained an injury to her chest, focused on attempting to save a dog that was injured in the blast, but senior charge nurse Charlie Fairhead was forced to leave the dog to prioritise the human casualties, and the dog passed away.
At Holby City Hospital's emergency department, Nell refused treatment, but she was taken into resus after collapsing near triage. Medical lead Connie Beauchamp found that she had a heart murmur as well as suspected eczema on her hands and asked for chlorpheniramine, but Nell continued to refuse all medication. Once her X-ray results came back, registrar Maggie Coldwell found that a small piece of metal had moved into her cerebral artery as a result of cerebral emboli and atrial septal defect, causing her to have a stroke on her left side. Regardless, as the medication she needed was tested on animals, Nell insisted on being left to die and claimed that she "never meant for this to happen". She confirmed that she had been handling explosives, but she stroked out on her right side before she could confirm there were more bombs. As the department was evacuated, Charlie was instructed to wait with Nell until the ITU team arrived, but Denny entered resus and disconnected her tubes, resulting in her death. (CAS: "Charlie's Anniversary")