As you can say in the next second in front of his eyes Alex could already see if a portal begins to appear and it already begins to get bigger and bigger. Naturally still it will take him some time to complete and Alex will enter that portal before that to kill those monsters inside of that place.
Actually not only him but most of the fighters right now are already doing the same thing and everyone of them could see those portals appear in front of them and not only that they already prepare themselves to enter those portals to kill Monsters.