A man with a knife doesn't inflict any bodily harm on either of two victims, despite the fact that he's already supposedly killed one before that? He rolls down the hill with one, a knife at her throat, and the story doesn't mention that there were any wounds?
Murderers are dangerous fugitives because once they've killed, they have nothing to lose by killing again -- yet this guy didn't even inflict any serious wounds on his next two victims? There's no physical description of the two victims, BTW, so comparing them to Levy's physique is a non-starter -- for all we know, they were as petite, or more so, than Levy.
He had gained control,he thought, relaxed for a moment, and the both savvy and lucky woman managed to get away. He didn't rape her and then leave her unharmed. She escaped, big BIG difference.
There is no question in my mind that the last victim was going to be killed when he was done, unless she got away from him.
Even Ted Bundy, quite practiced and skilled and luring, sexutally torturing and then murdering women, got scared away and had victims get away . This very young man - still on the rapist/murderer learning curve.