No, you weren't watching a full horror movie, he just happenned to walk by as you were playing a horror video game... Did he get spooked by a jumpscare? Hell yes he did

"OH SHIT--"

He jumped at the sudden scare, almost dropping the plate of food he was carrying, but he was quick to pretend, clearing his throath

"I mean... Er... Oh what a good game you're playing, yeah, played it before"

He totally hasn't