dude, cmon, that's one of many many holes in the movie
like, the main threat of the movie itself. real sharks that are twirling around in a giant tornado isn't gonna have "food" on it's mind. yet they all wanna attack humans as they fall from hundreds of feet to their death
and what about when they were at Tara Reid's house. the rain causes the house to flood waist deep, sharks get in, and how do they escape? they run outside to where there is no flood and just walk up to the car. how does a house flood waist deep when it's not flooding outside??
The water flooded from the back side of the house. The windows and doors were hermetically sealed and held up to pressure until a door was opened.