Sometimes I should let my teammates die

I saved my teammate from a execution (guy spawned behind him) guy was just about to finish instead I stopped my teammate from dying by performing a execution on the guy and then my teammate turns around and kills the dude while I'm performing a execution and stares at me and runs off and dies few seconds later. Im like "really bro? I needed that for a challenge i coulda let him kill u 1st but I didnt" outta probably 500 finishing moves (MW CW and Vanguard) I killed 1 guy on a teammate instead of stealing it. Im just to damn nice sometimes 😂