Amnesia

You decide to go back the way you came. You turn around and sprint.
After a while, you come to an intersection. You look round to see what's there...
...and see a whole SWAT team, obviously looking for you. Instanly, you are sprayed with bullets. You get shot in the fore-finger of your right hand, and the tip gets ripped off. You scream and fall backwards through the already shattering glass...