[ansel12]

So he just killed the guy just in case?

[Alberta's Child]

No. Most likely the cops were walking down the darkened hallway and they were startled by someone opening a door right in front of them.

I'd be surprised if the cop is charged with anything more than manslaughter or negligent homicide, though in New York City the prosecutors -- even the leftist ones -- can have a strange way of dealing with a case like this. Sometimes they'll go out and get a murder indictment that they know will never result in a conviction -- just so they can say they tried to throw the book at the guy, but failed.