Spoiler Thread: Avengers Infinity War

I read a very stupid theory saying that Loki is still alive and is acting like he's Banner. That would mean that Banner is dead because Loki would have made him look like himself. But once Hulk gets carried away by the bifrost then his spell should have ended and Loki turns back into Banner. Plus Banner wouldn't have gotten chocked to death not to mention the fact that Loki makes the tesseract appear, something Banner couldn't do. Do people even think things through?