Might be a glitch with aim assist and lag. We know the 1000 yrd stare has really high aim assist. We also know that it looks like the bullet came from that dude - not from your own gun. If it was your own gun, the purple bullet trajectory would've been different and you also would've died immediately after pulling the trigger - not the brief moment you had to get behind that fallen cache. Speaking of that fallen cache, I believe it's the key - Essentially what I believe happened was that you two did trade, however due to lag it seems as if he pulled the trigger second. Who did shoot first, we won't know, though it's very likely you two did it at the same time. That being said, our old friend lag registered it as coming second - it was likely the titan pulled the trigger when you were out of cover, but it was lag that didn't register it until you were behind cover. The reason it didn't register for him as a kill was simply because you were behind the fallen cache. The lag had tricked the game into thinking the bullet had gone through the cache and killed you, and somehow this made it so that the bullet did not register as HIS. I don't know much about code, but I do know game logic and how some sh!t is done, and thus this is my theory.