He could handle them alone if he drugs them with a sedative that takes time to take full effect ~30 minutes to 1 hour. He might even then begin to tell them what he is going to do to them. Sadists love to inflict pain and horror. Maybe a few girls have been able to kick out of his grip and run for a bit, but not get too far before the sedative takes them out, or slows them down enough for him to be able to pull them into his white truck with police light. Maybe that is why they were all small, drug users, and late at night, when they are worn down, tired, and now fighting a strong sedative. Easy prey for his cat and mouse game.