The Walton Waterworks in "Brave into the Valley of the Dead: Dark Day" is a special place in the game that is more complicated. If you want to play the Walton Waterworks, you can walk slowly to the left first. There are zombies in the first room, but it will not move, and as long as you walk slowly, it will not alarm her.
How to play Walton Waterworks in the Dark Day of the Dead Valley