I can only think the skill thief isn't too smart or careful about it. He supposedly kidnaps helpless beauties, but in reality he must not have done any background checks. Furthermore, he didn't even properly prepare for what happens after he kidnaps girls. After all, the girls are now out of his control and have taken over a piece of his private dimension, doing whatever they want.
Why I called the women stupid is because their one and only priority should be to get out of the place. Nothing else should matter, as long as they can do it safe and sound enough. They now snatched someone interesting enough for the skill thief to kidnap, whilst not being another beatiful girl, so their only concern should be to find out if he has what it takes to overpower the skill thief. Instead they started beating him up and threatening to kill him. How is that going to guarantee them any cooperation? They are morons.