Or your supervisor was playing you guys, she did call you all but pretended it wasn't her 🙃
Well here's the thing, that is a very big possibility, but they take it seriously and don't mess with each other about that kind of stuff. Now, I'm not saying it couldn't happen, but we're all very much of the mindset that we don't joke or mess with each other in that way.
It wasn't outright said when I joined, but there's this kind of unspoken rule. The place is honestly creepy enough, without having to worry about people messing around.
We've all been on the same level, for example, closing up, which we do each evening by calling out, mainly to make sure that no tourists are inside when we lock up, and there has been grumbling, murmuring, and even stamping in the last few months I've been there. Obviously, it's hard to say that it's without a doubt, that it's paranormal in those instances; it could be pipes, the house settling, or anything of that nature, but it is weird no doubt.