Don't open it unless its dark in the room your in, but you will operating blind.
Dr. Bruce Bugbee gave a good example in a video I liked below, if you can hold a standard novel/book and read the letters on its page its to much light.
Plants use red and green light and its a myth that these are night safe lamps, they still trigger photosynthesis. Now if they trigger the part that normally light does and destroys the plants hormones that trigger flowering is another thing. best not to risk it.
Plant need uninterrupted darkness as a trigger to flower, has everything to do with how much down time they have uninterrupted, if you interrupt it, bad things can start happening. especially if this happens a lot. Its why pinhole leaks in tents are a big problem.
If the humidifier runs out it will be fine for the night, its also better the humidify the air in the room the tent pulls air in from, then inside the text as their will be a lot of extra moisture and high and low spots that could lead to WPM and other issues. You only want aorund 40-50% RH in flower. anything more is problematic.
This is one of his videos. worth a watch lot of good information from him.
www.youtube.com/watch