Harry had taken to sitting as far from the door as possible. Anyone who came in, he was always the first target, and though some were careless enough that maybe he could have bowled them over and gotten past them, if he was quick and lucky - there was no way he could get out with everyone else. Or get out of the house entirely.
So he sat back in the shadows as best he could with Hermione and Ron and Luna and tried, fruitlessly, to come up with some kind of workable plan that could win them all free.
So far, they hadn't come up with anything, and the suggestions were getting more and more outlandish, and more unlikely. When the door opened, he lifted his head, recognizing he Death Eater in the doorway vaguely, though the light wasn't enough to really see properly.
He got up though, moving in front of the others. "Go to hell," he answered, automatically defiant.