So far, Rabbit's taking his "probie" position very well, setting out fresh fruit and making sure the milk isn't sour--in fact, Glenn thinks Rabbit's doing an outstanding job. Marisa doesn't understand why Rabbit is taking his probation so seriously, but Rabbit says it's because this is his last chance. His job is on the line if he messes up again.
Tyler and Boone prep their rig and Tyler wants Boone to drive once in awhile since they are now both paramedics. But Boone won't do it. Tyler still feels like a sidekick and he's sick of it. He wants to be "Batman." But Boone's not really budging from his alpha male role as lead paramedic. Meanwhile a traffic cop is run over and the driver of the car quickly absconds from the scene. Nancy and Glenn attend to Earl, the injured man, when suddenly the driver of the car starts shooting police officers from a nearby tower.
Marisa and Rabbit are en route to the sniper scene and find out that the sniper seems to be targeting firemen, policemen and EMS, but he is nowhere to be seen. Nancy and Glenn attend to a shot officer, who has a piece of metal lodged in his chest. Tyler and Boone are having trouble communicating with Rabbit while they hand off a patient to him in the helicopter, but Boone soon takes the lead to avoid confusion.
Nancy brings the injured officer to the hospital and Dr. Joe tells her that snipers usually don't hit just once and to be prepared for more shootings. Diana worries about Glenn going out there and tells him to be careful. When Glenn leaves, Nurse Jane tells Diana that she slept with him too.
At the station the next day, Captain Basra tells the team that the shooter is still out there, and still seems to be targeting cops and firefighters, so to be careful. To be extra safe, the team is ordered to wear bulletproof vests. Sela calls Boone and is extremely worried about the sniper and wants him to take the day off of work, and he agrees to do it for their kids.
Marisa wants to take the helicopter up and see if they can find the sniper, but Rabbit thinks it's a stupid idea and also, it breaks protocol. Since Marisa's not on probation, she's going to go and Rabbit says he's going to report her if she does it. Marisa gets mad, demanding that she wants "the old Rabbit back."
Tyler and Boone assist an older woman, Maureen, who is having trouble breathing and has stomach pains. She has horrible scars from a liver transplant and Tyler thinks her body is rejecting the new liver. Maureen is scared to go outside because of the sniper, but Boone assures her she'll be safe and Tyler tells her they wear bulletproof vests all the time for safety. Then, Tyler and Boone try work together as a paramedic team and Boone lets Tyler take the lead on this, despite his hesitations about it.
Nancy and Glenn help a man who is having chest pains but it's in an open area and both of them are worried about the sniper. The man is having a heart attack and they need to get him to the hospital. Nancy tells Glenn to focus on the job and not the shooter to help ease his nerves. Because of the sniper scare, paramedics are not treating patients on scene, but rather bringing everyone to the hospital, which has made the hospital incredibly overcrowded. When Nancy tries to talk to Dr. Joe about how the man she brought in is having a heart attack, Dr. Joe listens and tells her to find him a bed. Meanwhile, Diana asks Glenn if he slept with the Jane, and he admits it, but it happened before he and Diana got together.
At Tyler and Boone's next call they fall into one of the sniper's traps and they are both shot at but luckily neither of them are hit. The shooter disappears again and the police are back on the search. At the station, the rest of the team is glad to see Boone. Boone goes to see Captain Basra and after realizing that they are short staffed, decides not to ask for the day off.
At the hospital, Diana is having a problem dealing with Nurse Jane sleeping with Glenn, but Nurse Corinne tells her not to let it bother her. What bothers Diana more is that the nurses are talking about it--but then, Diana finds out that Corinne also slept with Glenn (and Rabbit) too. When Diana sees Glenn she asks him how many nurses he's slept with, because she's not a "badge bunny" and doesn't want to have to be tested for STDs. Diana thinks maybe it's better if they don't have a real relationship.
Two paramedics fall for another trap set up by the shooter, who hits one paramedic in the shoulder, and then gets his partner. Marisa and Rabbit make their way to the scene as do Nancy and Glenn, but no one is allowed into the circle where the injured paramedics are because the sniper could still be in one of the buildings.
As the police try to secure the scene, officer Ray is shot, twice, and the paramedic teams have to wait until the area is secure. Nancy radios to Ray to tell him how to make a tourniquet for his arm to stop the bleeding, but he is shot again, this time in the shoulder. Rabbit goes to make a move, but Marisa tries to talk him out of it.
Officer Ray is in trouble and the injured paramedics continue to be under gunfire. Rabbit isn't dealing with the sniper anymore and decides to take the ambulance and use it as a shield, and when the sniper shoots at Rabbit, he gives away his position. Rabbit makes it to the injured paramedics just in time as the police officers take down the sniper. Rabbit and Marisa help the paramedics and Tyler and Boone help Officer Ray. Meanwhile, Nancy and Glenn attend to the injured sniper. Although Rabbit saved lives, his maneuver broke his probation, and he could lose his job.
Back at the hospital, Glenn talks with Diana. She tells him she doesn't care about how many nurses he's slept with, but she wants him to not sleep with anyone else, just her. Glenn happily agrees to be exclusive. Boone tells Tyler he did a good job today and that starting tomorrow, they're equal partners.
At the end of the day, Nancy tells Rabbit that no matter what, what he did today was brave and the reason why she loves him. Rabbit isn't sure what he's going to do if he can't be a paramedic, but Nancy promises they will figure it out. Captain Basra tells Rabbit that thanks to him, all those men that were shot today are going to live, and pours him a drink. Better yet, Rabbit's not fired. Nancy watches on, smiling as an emotional and happy Rabbit leaves the office.