Holden did hate to interrupt someone who was reading but, well, these were strange times. Though, there was something comforting about someone doing something that's mostly mundane in a place that seems rather troublesome to say the least.

It's hard to decide what question is the most important. He could ask about his crew but he hesitates and instead goes for perhaps the more generic question... "What exactly is this place?"

It's a better question than Is this real, at least. The pain in his leg is enough proof to him that it's at least real even if nothing is as it seems -- or maybe everything's exactly as it seems which is more strange.