We had to climb another 'flight/set of stairs' to get to the roof.
He tripped on the bottom 'stair' and almost fell.
He waited at the foot/bottom of the 'stairs'.
(..) No escaping. Oh. I don't like it here. It's where they keep Riley's darkest fears. It's broccoli. The stairs to the biggest smite. Grandma's vacuum cleaner. Aw! Okay, come on. - Would you walk quieter. - I'm trying. (..)2015 Inside Out