A lightbulb appearing above someone's head meaning “I have a great idea” is because, A) a bright image like a lightbulb is a metaphor of a bright idea, a good and smart idea. ... So when someone has a bright idea, they're having an Edison moment, like Edison's bright idea of the bright lightbulb.
I think it is depending on what it it being used for. It is a little dark, but if that's what you're going for, it sounds great!
Flashback, to give the reader backround information
(Apex)
Do you happen to have a passage? If you do can you post it?
Or maybe you can tell us what’s going on so far?