All shareholders can UN-tender their shares. You only have to tell your broker to "withdraw" them.
Then, if you feel like it, in 7 or 8 or 9 business days, you can decide whether you want to tender again...or you can wait until (if) Brookfield wins and then you could tender in the 10 days after the offer expires. If Brookfield "takes up" the share before the end of the offer period, you still have time to tender for the rest of the period and the supplementary 10 day period.
Notice Brookfield did not say how many more shares they need to get to the 50%, so the only way to give another possible bidder the time to make an offer is to ensure that Brookfield does not "take up" the tendered shares early, by making sure that there is less than 50% tendered. That is easy because shareholder that tendered lose nothing by telling their brokers to "withdraw" their shares.
You can always change your mind again and tender when it gets down to the wire.
Didn't the OSC not stop the tender because they didn't want to remove the opportunity for shareholders to sell? What does 2 rejections by shareholders tell the OSC? Brookfield is an insider and we all know it.