Fan Flying In the Tower

So I was in the Tower, just dancing my thing with a few others when all of a sudden... We started floating up and down, almost (almost) like our characters were jumping on their own, but it was more like falling upwards. You can see two of the 'flying bobs' here in this video right before they cease, interestingly, when one of the guys leaves. It happened on the fan -- I wonder if this really is a glitch, and not just something cool, hmmmm... hahha.