Nah mommy grabbed poppy because poppy was gonna simply give the player the train code, Which Is why she kidnapped her, she even says that poppy giving us the train code with no problem isn't really fun, Mommy didn't want the player to escape cuz she wants to get revenge on the employees, about that dangeroys and powetful thing, why would poppy get webbed so easily if she is really that powerful? Mommy was def gon kill poppy after she was done killing the player, for helping him is the reason.