Thumping when the lights are off?

So Andy is currently in my room... long story short; we lost power to a snow storm and the generator (to give our house power again lol) may or may not have leaked some carbon dioxide into the basement through the basement door. I doubt it, But Better safe then sorry, so I brought Andy into my room just in case. The thing is, every time I turn off the light to go to bed Andy starts thumping and "hissing"....?? He's currently in his play pen (his actual cage was left in the basement, because he won't be up her forever) but every time I turn the light off and everything becomes black (so I can sleep!) I can here him hissing and thumping!!
What should I do??

Leave the light on... or listen to thumping all night. Maybe if you have a small light that will satisfy him and won't be so bright to keep you awake.

You could try giving him his vegetables when you switch the light off. I slept with the rabbits in my room for years and they tended to be noisy when I locked them in for the night (leaving them roaming in the room was just not possible as they jumped on me at random, waking me up ^^'). So considering rabbits are normally active quite late, I just gave them their pellets in the morning, hay all the time, and the vegetables when I went to bed (it occupies them for a while). That way, they settle down while eating and then go to sleep with their stomach full. You'll hear the munching noises but I found them quite soothing and it never prevented me from sleeping, contrarily to thumping / bar eating noises.
Like JBun said, you could try leaving the light on, but I don't think I could sleep with the light on myself (or maybe a nightlight?)

Thanks i'I'll try giving him his vegetables before bed

I hope it works for you too ^^

a night light may also help for a little while ...

Peanut used to thump all through the night and freak out when I turned off the lights. I got a little night light by his pen and he's a lot better with it. He thumps once in a while if the house creaks but besides that he's better