Is it possible to walk from the pedestrian area to the tertiary road on the bridge (Mölndals bro)?
If so, it should be connected in some way. Maybe a small length of highway=pedestrian (or footway) at each end of the area, between it and the road?
Also, the highway=steps at each end of the area - where to they go to? Is there a footway connecting them to the roads below?
How would you walk if you would want to go to (or away from) the specified place? Try to follow that same route using the ways on Openstreetmap. Somewhere that will fail - that’s where you have to add something.
For example, I see that there is a set of steps leading up to the area - but it is not leading from anywhere. Might perhaps the bottom of this set of stairs be connected to the road running alongside it? Or is there perhaps a path running to the area to the west?