The Guardians first theft was a test for the second, more important, theft. Then again, when someone wants you to steal from the collection of an immortal - a Celestial named the Collector - you know things might go sideways. I mean, he named after himself after his hoarding obsession! You know you're a hoarder when collecting isn't just the thing you do, it's so much a part of you, it's your name.
And The Collector isn't your run-of-the-mill hoarder. He only collects the good stuff. The one-of-a-kind stuff. And he's super serious about keeping that shit in his collection. He doesn't just have a space-museum, oh, no. The rooms can shift around. He has robots and horrors as safety, as well as a buttload of mines. And not just one kind of mine. Some blow up if an organic being shows up nearby. Some... I forget all the kinds, or even the others, because the organic-sensor mines stood out most. But Rocket listed off a whole bunch of kinds.
Drax still won't fight, which everyone figures he might have to. In fact, when he kills someone, he screams at them that it's their own fault, he tried not to fight them, and he won't accept that guilt on his conscience, nope, not him.
Gamora, however, is willing to murder everyone who gets close to her. Robot, not a robot, whatever, all the same to her. She also has a side deal with the buyer, as far as I can tell. Rocket is pretty much the same, while Groot is tiny. And The Collector is... far huger than I remember, but hey, Celestial. I'm willing to go with it, especially if the Guardians come out of this okay.