when Marv and Harry are trying to go from the basement to the upstairs, Marv uses the rope, then uses furniture to climb. Also after both are hit and fall they use the furniture.

However earlier it shows Kevin upstairs setting the tools to fall on Harry, then Kevin is in the basement turning on the power when Marv is trying to wash his face. Then when Marv is climbing up he sees Kevin on the first floor.

How is it that Kevin was able to go from the basement to the first floor so quickly and the robbers couldn't find the way?