When ever I shut off my uvb bulb at night I think my tortoise is asleep but when I shut it off he tucks into his shell really fast as if he's scared thanks for all the input!
My baby loves to ram my hand if i mess with him or his food tray . He's so grumpy hope he grows out of it . I set up my heat lamp and my uvb lamp in two timers . First the heat lamp goes off. Them ten minutes later the uvb lamp turns of . Making it go dark slow not all at one time . Hope that will help him not be scared.
The sudden light off while the tort is on a nod likely will startle due to the sudden light/shadow change....perhaps start some routine with him so he is not startled ....like gently talk over his enclosure as you are ready to turn out the light or gently touch him at lights out...whatever you find is gentle...