Well, I posited a theory about Kim not wanting to give Mangum a ride because the guys wanted their money back from Mangum and Kim may have been afraid the guys would chase them in the car. so she wanted Mangum to either leave the money or get her own ride, which may have been what was being discussed in the bathroom.
Maybe calling 9-1-1 (and being so explicit about the address) was to get the cops over there so they could either go back for Mangum's stuff while the cops were there or else because they were afraind the guys were going to follow them. They may have been sitting right up the street watching, ready to drive up (or Kim drop Mangum there), if the guys opened the door to the cops. Since nobody answered the door at the house when the cops arrived at 12:55, there would have been no way for Mangum to enter to get her stuff and maybe get the cops to force the guys to pay up, which could also then and only then (because nobody answered the door so she couldn't get her stuff or her pay) become the motive for the false rape charge. Maybe Mangum was afraid of a beatdown so she didn't want to go home, and she was too drunk to drive, but Kim wanted to get rid of her, so she just wasn't going to budge from Kim's car.
It's just another theory.
Welcome to FR--BTW I like your choice of friends ;-)
Since Kim and Crystal didn't know each other, I wonder why Kim cared?--maybe they share the same pimp?--
good theory on possible motive for the 911 call
Whether it is likely IMO depends on if the accuser was really unconscious at the time she was placed in the car, then less likely to be the case