For a power outage I would be more stressed about the grow room rather than the flower room. The reason I say this is because a power outage in most cases is only for a few hours up to a 24 hours. If the power outage is any longer than this then there are more problems on your hand than your grow, such as the perishables in the fridge, the use of your computer to reply to this thread. Charging your mobile phone for the need of emergency calls. So to answer your question, I would just leave the flowers the way they are, its not going to revert them back to veg state or anything, it might put a little stress on them but nothing to to really kill your crop. But as I also said, for your grow plants get them into the outdoor sunlight if you can, you don't want them sent into early flower