I handled myself pretty well with the jump scares but one did catch me off guard for sure
The scene with the stalker was creepy as hell. Both when she met him and the second scene with him.
Also the opening sequence was great, but once the movie was over, I was confused as hell how it at all related to the movie. It was clear to me that he must have been infected, but he never passed it on..
Sorry dunno how to spoiler anymore so tried being as little descriptive as possible.