I might hesitate in killing someone who is not originally a criminal but these guys are real criminals, they are the worst of all the worst and they deserved to die. If this incident is not prevented, there will be 20 student deaths and 129 injured. Not only that but they also have been able to become really dangerous after they escaped prison. After their escape, they became one of the most wanted people in the world and are deemed to be the "shoot on sight" criminals and due to their escape in their confinements, it resulted in more deaths in the process.
Now that I returned in the past, this matter is not something I can just pass by and do nothing. If being a vigilante can help reduce the injured and stop deaths, then so be it.
After killing the bastards in the room, I look at the students in the classroom and check if anyone is injured. Seeing no one is seriously injured in the process, I look at the girl who was being choked earlier.