Call Him out

“What?! Are you trying to imply that I, Mr. Mystery, have created my own exhibits? I can see you’re quite the connoisseur of the supernatural, squirt. After the tour, I’ll show you some exhibits so horrifying that they’re not permitted by the state to be shown to the public!”

The rest of the tour flies by pretty quickly. The old man pulls you away at the end of the tour and leads you to a pit. “This is the Bottomless Pit. As you can see, it is clearly bottomless.”

You begin to explain why a bottomless pit is impossible, but he stops you. “It’s bottomless, kid, end of story.  Trust me, I know. Whaddya think of that?”

Explain the concept of Bottomless to the old hack.

Give up arguing and leave.