I've watch this trailer about 5 billion times so I noticed a couple things.
I think the scene (his first appearance in this trailer) of Thanos removing his helmet is when he rolls up on the Asgardians because he doesn't seem to have the Space Stone in his gauntlet yet.
I also think the scene where he's holding Thor's head () is from that same scene on the Asgardian ship. Because Thor isn't with any of the other Avengers (except Groot and Rocket) in either trailer we've seen.
So Thanos kills the Asgardians, gets the Space Stone from Loki....probably kills Loki, beats Thor's ass and Thor either escapes or he's tossed out of the ship, then he runs into the Guardians Of The Galaxy.
Fred.
I don't think they'll kill off loki that quick, you think? *other's voice* "you think you know pain"
I think Gamora's narration about Thanos is her talking to Thor on the guardian's ship.
Just forgot, they gave us this trailer and we still didn't see the thanosthrowingthemoonshot in the trailer