Assume this very simple position :
White : K anywhere, B b7
Black : K anywhere, R a8 , M behind R
After 1.Bxa8 any 2.Bb7(M emerges) .. ok, this is not quite what i had in mind when i typed that comment (I was under the impression that the 'emerging' is a separate move,) but the Marshal is under attack. Unless it can get outa there quickly (which is difficult in the usually crowded positions this game gives,) it's lost.