They really do, but yes, let's deal with the elemental, especially since it's taking up all of Childermass's concentration as he struggles to keep the creature still. It struggles, but can't move its legs, keeping it nicely in place for Yuuya to aim. Iron, though, is what makes it a quick end.

Just as the changeling had claimed before, it goes through the elemental's head like a hot knife through butter. A crowbar honestly shouldn't be able to go straight through rock like that, but it does, the iron passing through with little resistance and leaving a blackening hole where it went through, right through the head. It gives a pained jerk, entire body giving off one last, futile struggle, and then the fire powering it begins to die down. Its struggles grow weaker, weaker, though Childermass hangs on to the shadows trapping it in place, just in case.