First of all, your PU should have been watching R3, not the play at 1B. Because of this, you could have thrown him under the bus; if he were watching what he should have been watching and you asked him, what would he have said? "I don't know" or "I was watching him" wouldn't look good for either of you.
No rotation on this play, wasn't a clean hit. But I would say that you should make the call then ask on appeal. In the event it is a rotation or the PU is watching R3 cross the plate you might be throwing him under the bus.
