Continuity mistake: When Ray Liotta throws Madeline Stowe on the bed after she pulls the gun on him, he used his hands to pin her arms down. Then they cut to a different angle, her arm is pinned under Ray's leg and he's grabbing her hair.
Continuity mistake: When Ray Liotta is threatening the burglar, a door on the left side of the screen is closed. In the shot when Liotta says "he wants to kick your ass!", the door is wide open.
Continuity mistake: When Ray Liotta is lying unconscious at the end just before getting shot and killed, the blood pooling under him changes volume and position once and then back.
Answer: Pete was a psychopath and a murderer who did not think or act in a logical, reasonable, or restrained manner. He had become so enamored of Michael and Karen and their affluent lifestyle, that he went to extreme and dangerous lengths to ingratiate himself with them. He was not at all rational.
raywest ★
And also, his years of being a patrol cop and seeing the brutality of society on different calls may have made him snap. I mean, look how heartless he was-he throws a naked woman out into the street in a dark alley and leaves her there after having sex with her in his patrol unit, no regards for anything or anyone at all.