Chrono's moving from point to point, still doing what he can, when he hears the shout from relatively nearby. He doesn't even bother to look and see who else is around - he just rushes over, and assesses the situation quickly. That mostly means trying to find the best way to move things aside. He doesn't even ask, for the moment, how the man knows there's someone under here. That's not important now. "Guide me! I can't see them, give me an idea of what to move!"

There's too much debris here to just move it all, but that's why he'll ask first. Work smarter, not harder. Or more importantly, slower.