To start the mission, the player must find any of three locker keys scattered around the Blackrock region. Each key unlocks a locker in prison guard barracks at the Blackrock Prison. Finding and using all keys will complete the mission.
After the first time, it is impossible to crawl through the infirmary window again, but with a bit of wiggling it is possible to step up the tiny ridge (on the left side, near two "chimney" pipes) which separates you from being able to jump down to the doors of the infirmary. Thus saving you the return trip around the wolves.