I’ve sometimes had the Clone #6 fight end normally and sometimes with Valiant deciding to shoot Pritchard and 47 after killing #3 before the tour reaches him. As best I can tell it’s random, with each thing going wrong on the tour raising the chances.
So after a few tries with the Arcade, I started leaving #3 until after they passed him so fighting #6 would reliably not trigger the “kill Pritchard” sequence.