"Swift Vengeance Waits" is the 1041st episode of Casualty and the 37th episode of the 31st series. It was preceded by "Roadman" and followed by "Do Not Stand at My Grave and Weep". The episode was directed by Judith Dine and written by Rachel Smith.
Ethan is dreading clearing out Cal's locker, but manages to do so with Alicia and Charlie's support. Finding Cal's stethoscope in his locker, Ethan wears it as his own, as a way of always remembering Cal. Shortly after, Ethan is angry and confused when he receives a phone call telling him that Scott Ellisson has been released from custody due to lack of evidence. Meanwhile, Jez wakes up in bed with Mickey, but is furious when he learns that Mickey is planning on joining his family at a local right wing rally.
At the rally, things spiral out of control, and Mickey ends up chasing one of the Muslim protesters, Nasreen. However, she manages to defend herself by turning round and pushing him into a wall, where he falls in injures his abdomen. As Nasreen is running away, she trips and hurts her ankle on a drain. The paramedics arrive and Jez is shocked to find Mickey, as he and Nasreen and taken into the ED, along with Denise who is quick on the scene to accuse Nasreen of assaulting Mickey.
Ethan is shocked to see Denise and Mickey back in the ED after the events surrounding Cal's death. Denise is bitter towards Lily and Ethan, recalling what she still assumes was the doctors' negligence causing Roy's death. Ethan is midway through treating Mickey when Scott bursts in, demanding to see his brother. He's sent to wait in the relatives' room, whilst Ethan is in shock, having come face-to-face with Cal's killer.
Nasreen's mother Fadila arrives, and has hot coffee spilt on her neck by Denise Ellisson in an alleged accident. She's treated in cubicles, and tries to get Nasreen to stop getting involved in the protests against the right wing rallies for her own safety.
Ethan goes to the relatives' room and questions Scott about Cal's death. Scott angrily taunts Ethan with the fact there's a lack of evidence which results in Ethan lashing out and becoming involved in a fight. Iain, Jez and Alicia soon intervene, and Ethan admits to lashing out at Scott. Elle tells him to go home for his own sake, not out of reprimand. Nevertheless, Ethan ignores her instructions and returns when Mickey's condition worsens. Speaking to Scott outside, Ethan tells him to admit that he killed Cal in order for him to save Mickey. Scott still denies any involvement, knowing that Ethan will save Mickey anyway, which he does.
Lily walks outside the ED looking exhausted and needing a breather. Iain sees her and tries to get her to admit that she needs some support after her accident and there's a hint that he can help her but she rebuffs and sticks to her story that she's fine.
Mickey is saved and Denise and Scott are relieved. Ethan takes a walk outside the ED for some fresh air and is comforted by Alicia. Alicia makes him view the situation in a new light, reminding him that nothing he does will bring Cal back. Scott walks over to them and apologises for their scuffle earlier, agreeing to put it behind them. He thanks Ethan for saving Mickey and that he hopes who they catch who killed Cal.