At 300,000km from Earth, the gravitation field from the Earth is effectively 0.
How do we have a Moon then? It would have floated away from Earth by now if the gravitation field was effectively 0. We also don't know the real distance from Earth the scene takes place, and we don't know the meaning behind the phrase. It could as well mean the current velocity has put the ship on a trajectory that will be intercepted by Earth's gravity.
I also just saw the film again, and I must admit that I was wrong. While the implication is clearly there, and in fact the ship is always aligned so that the people are falling towards the Earth, everything is vague enough that it can be interpreted in any way you want, and in no place a connection between Earth's gravity and the people falling has been established. Sorry, I was going on by the memory of my earlier impressions.
Oh, and let's not forget... The moon's gravitational pull obscured our warp signature.