You shouldn't leave your kids without telling them.
Betty's father had a heart attack while Betty's kids are playing in the back of the house.
Betty needs to get to the hospital immediately.
Betty pops her head out to tell her kids that everything is OK, she just needs to go out for a bit.
Betty just picks up her keys and leaves the house without another word.
Betty's kids know where their mom went, and are able to keep playing unconcerned.
Betty's kids are confused, and scared that they don't know where their mother went.