Yes. This is what you think it is. This is a door serving as the walkway to a door. It's hard to see in this picture, but the door is spanning a small ravine that I assume was dug to make way for pipe or wiring or something. This is such a common sight in Saudi Arabia.
Not that it's common to see doors on the ground, but to have a giant ditch in the middle of a sidewalk and a ridiculously narrow "walkway" put down across it is the typical modus operandi around here. I guess the city doesn't provide those steel plates or a temporary walkway like you see in more
"Let me get the door for you!"
This kind of thing would have totally baffled me last year. Now I just whip out my camera and snap photos because this is the kind of stuff that happens in Saudi Arabia that is so hard to describe.