"It knows we're here, and it continued to come back after every reset, I find it hard to believe that it would retreat so suddenly. If it was injured maybe it's gone off to lick its wounds, but surely we would have seen that?"

Unless that's what the water column was, but they should have seen it ascending into the sky, even for as dark as the eternal night is. It would have blotted out the stars entirely as it fled.

"It almost seems too quiet doesn't it?" saying what they're both thinking, that they're just waiting for movement, on edge for this to be some brief moment of hope that will be dashed when reality hits.