>>191782250BMG is about 19,000J of energy.
This is the S&W500 magnum that only has about 3,500J.
A 50 BMG fired in your house will blow out windows, damage walls and ceilings and pretty much blow the paint off the walls.
If you hit anyone you can scrape them up with a putty knife.
It would be a big mess all around. The fool firing the gun might need the EMTs though. The blast in an enclosed space would probably knock the shit of them.