Having some overbearing mother zombie character rubbing vapo-rub on them might actually work. Vaporize them.
Usually some freaky character will step up to the challenge of engaging the generally undeveloped idiot. The crowd changes from no longer a source of attention getting to crowd sourced humiliation. This wakes them up that they maybe haven't thought through really being an idiot far enough. There are a lot of freaks that have seriously done their homework on what is wrong and no matter what they think they have developed in being a professional idiot is going to result in totally unexpected results here. It isn't going to be like all the other times they were an idiot. Are they up for the challenge?
If it goes to defcon 5, the haunt is as much entertaining as possible physical torture. Total removal of any security. Even a place to keep someone restrained in a section. They become part of the show in a jail cell asking to get out for an hour or so. Memories for when they work themselves to a real prison and they should have heeded some mental or social warning.
Security guards are to make sure no one is hanging around at the ticket booth where the money is being collected or parking cars. You will find police uniformed or mixed into the actors will not engage people at all. They work by detaining people and questions, wasting their time and life and moments, that's it. Actors can do that. What would normally look like it might spoil everyone's fun becomes everyone's fun.
For all of these reasons, most people behave themselves rather than create some situation that could go beyond the bounds of their personal entertainment.
To run a haunt you really should develop cult leader skills or be able to insight a public riot skills. Uniforms tend to attract a different attention. No reason to make a crowd have that tense feeling in their stomack over some idiot or that the tense situation with that idiot was what stood out during their visit.
Another fabulous post from the U.S.Department of Wild Imaginings, now in spectaclar stereo, sponsored by the Adhesives and Sealants Council, suggesting ways to stick things together since the 1800s. Not fabulous in a gay way. Your results may vary. Illinois residents add 8% sales tax. These posts have been made by professional post makers, do not try this type of posting on your own without extensive training, lovely assistants and a trusty clown horn.