Cox, who had achieved peace in the village by closing it off and reducing the number of mouths to feed, attempts to get rid of the heroes, but then a monster's voice resounds throughout the village. Yotsuya and the villagers are powerless as a multitude of monsters swarms the village, as if under someone's control. After determining that it would be impossible to defend against the monsters' attack, they decide to flee the village.
so if we assume it's 40 meters, 
we just need enough for that much.
،فيمكننا افتراض أنّ العمق 40 متراً
أي نحتاج ذاك الطول
Das ergibt etwa 40 Meter.
hay que hacer lo suficiente
para 40 metros.
hay que hacer lo suficiente
para 40 metros.
Alors, on devrait considérer
qu’il y a au moins 40 m.
quindi, se ipotizziamo che siano 40 metri,
ne servono per quella lunghezza.
então, se presumirmos que são 40 metros,
precisamos do suficiente pra isso.
Если считать, что там
сорок метров, то этого хватит.