check out what happened at ATCVictoria's offer was upped by Hecla. Mind you, HL is in the middle of their takeover of Alexco.
What this means is that just because AEM is in the middle of the Yamana takeover it does not preclude them from making a bid on Sabina. SInce the entire universe knows that B2's bid is woefully inadequate, it would behoove AEM to make a legitimate bid on SBB and not let B2 into their own backyard.