In an abandoned police station there are likely interesting and useful confiscated goods. In the locker area, which is unlit due to power failure and absence of outside windows, there is also an intensely foul smell. It is coming from one locker specifically, which is already unlatched, but not open enough to be able to see in.
If the player decides to bust it open, he/she will be greeted by a mutant with rotting flesh who hungrily tears in to the player. If the player is very cautious, they will find a corpse of said mutant instead. There is valuable loot on the floor of this locker, and the player is rewarded for their bravery/caution appropriately.