If McInnes genuinely wants to go to The Rangers, it probably is for the best that he is, at the very least, allowed to talk to them - assuming some kind of agreement has been reached that they can actually afford to pay the compensation due to AFC. Who knows, DM may decide, once he gets to peek behind the sevco curtain, that just like Sunderland, he's better off staying where he is.
If he decides to leave, then, after we've had our head's gone moment, we'll just get on with supporting the Dons and who ever the new manager is.