Once they get to the intersection (and make sure there are no ambushes set for them), Tanya sends all the prisoners to stand against the wall, then places a metal cube at the center of the room. "Annabelle, Bonzo, turn your back to the open space... it will get very bright in a moment."

And it does, as space ripples with light effects, and a large armored personnel carrier appears where there was nothing a moment later.