The look of utter terror on her face when he says some of these things. She is VERY afraid, and it's not the type of fear you get merely from things not going your way, that's the fear you get when the fbi shows up at your house with a tank.
The chance of him throwing more than one a few feet from himself would be low if they are conventional shrapnel grenades. For sure, the guy who covered his ears on the other side of the table would have been torn to shreds, if he lived, he'd not be worried about his ears at that point.
According to some records, there are a number of deep underground military bases that were built and almost immediately abandoned by the military. This has happened with many above ground facilities too. There are theories about demons and such that come from this behavior, but the obvious answer would be that the military built the "base" for a company or some other purpose (perhaps a black site). This holds true for the above ground examples for sure..