In Hermione's mind there was no reason to bring up the fact that the door was closed when she was attacked in the Atrium unless Rabastan had plans to use the knowledge against her. He had never been the sort to sit on information that could be used to his benefit. If she was found to be responsible, or at least possibly responsible for helping a prisoner to escape, she would no longer be standing in his way. It might have taken over a decade, but he'd be the one completely in charge.