That's an extra good point. He's admitted, I think only twice, within his series that he made a deal with Thanos in order to escape. This arc doesn't include such a deal. And Quill has never mentioned such a deal to the members of the Guardians (that I recall--feel free to correct me if I'm wrong). It stands to reason that it wasn't included in the narrative he provided here because he still doesn't want Gamora to know the truth.
As is often the case with THIS series in particular, the explanations that readers have posted here are far and away better than what was actually stated in the comic.
As far as I'm concerned ALL OF YOU who have posted in this thread have a better sense of what this story needed than the guys who actually got paid (REALLY well I'm sure)to mash it together.
Is anyone else really confused as to how Gamora was able to cry at the end of this issue? Didn't Thanos remove her tear ducts? Because I remember reading in Warlock and the Infinity Watch that he had.