Upon hearing the other voice, he takes evasive actions while still on Clawshot's tail. Though normally not the greatest at turning, in these smaller spaces Machbreaker didn't need to turn. He lifts up his form a bit and rides along the walls, avoiding the blasts. He swiftly transitions to the ceiling and turns back into a bot after passing Clawshot so that he lands on top of the crane when he falls down.
Meanwhile, hearing other members in this, Railgun switches to his artillery shells and sends several blasts down the hall after them. He turns into the train and charges forwards to catch up, whistle screaming.
As Spirit takes out the cube, both hear several loud explosive shots coming from inside the walls. Tie-Grabber had noticed a blast earlier, but one shot wasn't uncommon. This many however, along with the sudden call of the whistle, meant there was trouble. He swiftly reverses what he did to the hatch, locking it, and has his arm loosen up back into its typical crane form.
He swings it out and latches in a crack in the ceiling and goes to swing away from Spirit. Based on the noise, he had a good idea of where they made be headed. After all, most of these trails are his design and he knows where to knock them down. The only thing is need to get past this weird person.