I was playing brotherhood last night and there was a level 50 on the other team who was un killable. I was playing manhunt and every time I had them as a target I would get about a medium distance away, I would then lock onto them and they would do a dead sprint right into me and stun me. I never even got the option to kill them.
So were they cheating? or is there some perk that makes you un killable ( I know about mute, but I know for sure it wasn't mute.)