Wow he didn't even know what is flood?

Well If you dont live in that area you wont know when the tides will come, plus he got stuck on a quicksand so its difficult to get out from that

You don't need to live there to know what is flood. Even people who live in the desert area know what is flood.

Its not even a flood its high tide, as you can see the seme is absorbed in his world which makes him an idiot. And tides are sometimes different, sometimes the water goes up slowly while sometimes they go aggressively with waves

But he said "flood, what...what is THAT?" Okay i'm done, bye.

It could be because of the translation, just imagine. Does it flood in the sea?? When the water comes back at the beach what is it called?? And where can you get oysters and shells?.

The thing is the seme is too far in the beach, then he got stuck on the sand which is probably quick sand then the water comes rushing in. Next thing you know waves of water came. When waves hit you they will put you underwater and you will be unbalanced and the current will drag you in the middle of the sea. Thats why its dangerous to swim at a high tide ٩(๑❛ᴗ❛๑)۶