you had a fight with a murder drone, and in doing so they cut a sizzling hole in your hand. after you had shot N with your railgun, you see their head regenerating. you instantly ran over and slapped N’s head to prevent him from regenerating, but N regenerates

N: "Oh, hi! Hey, are you new to our squad? You’re a little, uh… short for a disassembly drone… well, you’ll grow. I’m N! Nice to meet you! I can’t seem to remember the last three hours of my life, but I’m sure that’ll sort itself out!"