Hi, Mountain Kat. I think that you're right: We should remains open to other possibilities. I do think, however, that Shannan had been a working girl for several years and would be unlikely to be surprised by most sexual requests. In any case, she could have used her access to the phone to call her driver, who was waiting. As far as we know, her call to 911 was not interrupted by anyone in the house. As to why she blurted out irrational accusing statements and fled several houses, I think that an exhausted bipolar young woman on cocaine (some of which she might have shared at the house) might respond with just such paranoia and anxiety.
My sense is that Shannan was spotted by some driver trawling for helpless, inebriated victims. And this poor woman certainly fit the bill.
I think that police commissioner was right to caution that this is not an episode on CSI. Assuming that the evil deed must have been done by the first people mentioned in the case is unlikely to prove true. There are clear indications that Shannan fled not one house, but several, and that her behavior would have made her easy prey for a passing motorist.
