Reported as in reported for duty.
Originally Posted by Ignatius
Bernie speaks about the time of the explosion, so yes, he heard it.
Or he, say, heard about it from another guard (the ones he was standing next to in the picture, another visual element!). How loud was the explosion? How far did the sound carry?
He doesn't say he heard it, nor does he indicate he was on duty at the time, that's an assumption you're forced to make. To my mind for this to be pure logic the puzzle would need to show that only the guard on duty at the time could have heard it, otherwise you have to assume that over the many other plausible explanations.
I just think it's a sloppy puzzle.