Happenglance
while you stare for an uncomfortably ridiculous amount of time at a person, pondering your thoughts around whether they look/are/or remind you of somebody, they 'happen' to become aware of your interrogational viewing and look straight at you
Is that? No it can't be, or could it, he's got. Damn! he knows I'm looking at him and he's looking at me, it was a 'happenglance'