what was the red object on the wall in the sanitarium?

Right after Carol tries all of the locked doors in the hallway in the sanitarium, there is a close-up shot of her face. The focus then changes to a red object on the wall at the end of the hallway. I have a really small television and couldn't make out what it was. It kind of looked like a cross between a fire extinguisher and an enema bag. It must have been and important detail if the film purposefully draws your attention to it. Can someone tell me what the heck it is?