Continuity mistake: At the pool when Sean and Molly are lying on towels discussing their families there is a shot focused on Molly's face, and she says she has a big family and people refer to them as "The Brady Bunch." In this shot you can see a very distinct blond haired man in the pool behind her. The shot then changes to a wide shot showing both Sean and Molly again and the same distinct blond haired man is now behind them on the other side of the pool. (00:14:54)
Continuity mistake: When Ally is thrown in the pool she climbs out and sits behind Sean and Molly with soaking wet hair however a couple of shots later her hair has partially dried itself. (00:15:57)
Answer: It's hard to say why she wants them to eat peas. But she does say that there could be anything in there even poison. My guess is that she might have poisoned the food.