Swim
If a tsunami is going to last an eternity you better learn how to swim now. We'll be under water for the rest of time and if you can't swim you're not gonna make it.
Picture most of the earth's population already swimming on the tsunami that will last the rest of eternity. Your floaties and life preservers would help you through this mess. You need to swim!
えい
およ
None
Oy (およ)! Oy, stop daydreaming about swimming and actually do it!
Picture yourself swimming in the tsunami with everyone else. You can't really talk to them, you're too busy swimming for your life, so you just shout "Oy!" to them and they shout it back.