lights are off except exit signs and emergency

I walked into my pf around 6, a normal time for me, it's packed. and the lights are off. computers are up, tvs on, music on, but all the lights are just off. maybe 10 minutes ago they came back on for 5 minutes and then went half off, and then a few minutes later went all the way dark. not dark enough to bump into things, unless you had limited visibility. treadmills working, there's enough light from a few windows to keep the majority lit enough but i just wonder if they're dealing with power issues. i know a majority of the machines work based on the work people put in, so i don't see how an influx of people would do this.

tldr; all the lights are off in my pf, every 10 minutes they change, im just confused