Painted Door.

One thing which James Xavier might have seen that upset him was the paint on the door of his room at the carnival.

There was a blue door in his private quarters at the carnival. And it seemed to have panals outlined with red paint. I don't know whether there were actually panals in the door, or if their outlines were made with red paint. The other side of the door didn't have those panels.

And some of the red paint was dripping down.

That might have been the product a a tight schedule and not enough time to finish the set properly. And possibly that might have upset Ray MIllard or Don Rickles to know they were in a movie being made so cheaply.

But possibly if asked Roger Corman might claim that it was deliberate artistic touch. Maybe it was something which Xavier had painted himself for some reason, revealing his mental state. Maybe it ws supposed to foreshadowing of the final scene.