The concept is pretty cool! Depending on who you listen to and act, it can lead to differents dialogues. The dialogues flow very organically depending on your single action of turning the lights on and off.
Although, it was not always clear to me exactly who I was listening to, given that the characters switch frequency often, so maybe using different text color for each character might help? Additionally, it would be useful to know which position of the switch turn the lights on and which turn them off.