It is conceivably possible that the woman's first words on entering the cab were a proposition. Your 3 seems odd; I don't pay taxi drivers until I arrive t my destination; since this cab ride never got to its destination, why would the woman take money out of her wallet? Further, there is no evidence that these two people actually had sex. The woman's pants were off, but as you say, she could have done that herself. A possibility that is consistent with evidence is that the parties agreed to have sex, but the woman passed out before the act could commence. Another possibility is that the woman passed out and the cab driver was about to take shameful advantage of that when the police arrived, but had not yet gotten to the point of actually committing sexual assault. You should know that mere intent to commit a crime, or even preparing to commit a crime, is not in itself a crime.