OK guys, we had a couple of "rookie" umps, (me & partner...dangerous situation...LOL). We discussed it and and came up with 2-bases from TOT (there doesn't need to be a throw to enforce this, I've been told) Not being sure if we made the right call, I've asked my mentor and other experienced umpires.
My only consultation in this is that they are split 50/50 on if B4 is placed at 2nd or 3rd.
Nobody else on the field had a clue, so they had to buy whatever our 2-man crew of "rookie" umps were selling!!
Brief explanation, and the game played on.