The children sneak out of bed to set a trap by the window. The purpose of the trap is unclear, but a logical conclusion is to make Santa trip and fall, causing a commotion, and thus witness him to prove his existence. Helen bought a Santa costume and happily considers dressing up to fool her children into believing that Santa is real.
The children sneak out of bed to set a trap by the window with the intention of making Santa trip and fall, creating a scene that would allow them to witness him in person. Helen purchased a Santa costume and is considering dressing up to trick her children into believing in Santa Claus.