Well, I kind of forgot about that one, but you can somewhat explain this since Mindlos is supposed to have taken a more perfected version of the serum. I think it was established that he can immediately take control of people, at some point in one of the past updates (I think Samantha said that after she joins MC). Perhaps once he actually manages to break through the MC's influence, his takeover is immediate.
Now that I think about it, there is a possibility that the MC may use his power over all the girls in the room, and knock them out due to that control override feedback thing, like it happened with Samantha, but Mindlos would still be there with a gun, and the MC still tied to the chair...