So here's the deal. I don't play, but I guess in Halo if someone on your team kills you, you get "betrayed." So here's how it goes. Blue guy 1 kills a red guy. He runs to hide and a vehicle known as a Warthog lands on his head and kills him. Blue guy 2 notices he "betrayed" blue guy 1 and they're both all, "WTF?" It gave me a chuckle to see how it happened.
And here's something funny. Here's Online Halo where this one guy ONLY "betrays" his teams. It's pretty good to hear the nerd's reactions. Also, in the game, you play capture the flag. At 8:12, you get to see him betray someone with the flag.