Kuai will fight to the very end. Can you spine rip World Eaters? Because he most definitely would. He definitely wants to kill the thing, letting it go to potentially become someone else's problem is basically the same as failing to him - either deal with it here, or die trying.

That said he would definitely sacrifice himself for everyone else even if that means closing the portal and staying here alone, or being a distraction while someone else pilots a drone. He would want others to be able to evacuate, but he wouldn't do that himself so he can be as far from the portal as needed.

Currently he thinks Weaver's plan of making another, bigger, bomb is the best bet and he's willing to do whatever it takes to make this happen. Depending on how large the World Eater is he could theoretically freeze it, but if it's huge (larger than a city block) he might also overextend his powers doing that and knock himself out - which means he wouldn't be able to fight so that'd be a last resort.