I can be doing something with the monitor(s) right there and still swear I hear one of the babies waking up from a nap. So I go check and nope. They're in my head..
I did that all the time till i invested in a video monitor... Best thing i ever did stopped me getting up at the slightest peep, we use to have a neighbours dog bark all hours and it would honestly sound like my son stirring through the monitor but it wasnt hahaha