The only thing can think about is that the reason this guy didn't turn on the lights is to see if he could capture anything without the lights reflecting on the camera and getting lights on the camera that wouldn't be there if the lights had been turned off.
I say this because I have had investigations done in my apartment and I have seen how they turn out all the lights to see if they can get pictures of things that can't be seen with the naked eye or that wouldn't be normally seen if the lights were on.
I have gotten some very odd pictures myself with lights off and on, but I wanted to try out the theory to see if anything would appear on the camera or whatever. The lights off made it to where even a black mass of whatever would appear even with the flash on, or a portal would appear with the lights off.
But it is a good point to try to understand why people don't keep lights on. I know I am terrified of the dark and for good reason, so I sleep with a light on and I have my house well lit throughout the night unless for some reason I am either not there or if I am trying to take pics or whatever. I also don't understand if someone is going through some strange activity, why don't they keep the lights on? Its common sense right?
Anyways just thought I would throw that out there, I am not sure that this guys pic is real or not, it could be a hoax, but remember we are not there and we haven't seen what this person has seen or not seen. The situation could be a hoax or it could be real, I don't know.
Just thought I would give my opinion on this