That was most likely his kink. Feeling empowered by scaring women. Sex would have been the last thing on hos mind.
Then again...maybe he had watched too many pornos and thought that was the only way to attract a woman.
...and then again...having had one nutjob strip off in a crowded tube train, central london, in the middle of the day, and proceed to wank in my face...he may just be suffering mentally.
Who knows? People are weird.