The arrow could remain elongated on one side (above) or it could be cropped (below)...
...and rotated to show up and down
These would be used for all major signage and could also be used as part of a chevron pattern for inner building walls or even external courtyard walls.
From this experimentation I used different orientations of the cropped arrows to create a range of ideas for a lift symbol (top) and a stairs symbol (bottom). Both final outcomes are displayed with the boxes.
Lift:
