The top of Topanga is a nice place to over look all the valleys (July 4th being the best), we live in a very populated city so seeing stars is hard from our homes. We do have wild peacocks in the hills so that could be the screams? Everyone and myself personally would never drive up that trail you park and hike up. It’s definitely a party spot and has been for years.
I doubt that peacocks would scream at night. (Based on my limited personal experience, I'd expect them to be up in a tree by sunset, with their head tucked under a wing.)
A question, though. What does a mountain lion scream really sound like? Traditionally, it's supposed to sound like a woman screaming.... but could it be mistaken for a man in distress?
However, it seems amazingly unlikely that a random animal/bird sound was mistaken, by pure coincidence, for a person in distress, on the very night that MW's car ended up lodged on a mountain trail.