The fire escape itself must be structurally correct in order for it to be accepted by the viewer as something that could actually operate as a fire escape in real life.
I mentioned before about keeping the background painter in mind when doing a layout. Here’s a really good example of this. You don’t want to overly burden the painter with a lot of unnecessary detailing that will take an extra hour or two to properly paint. Remember what the focal point is for the scene. In most cases, it’s the character. If a character came running up from the bottom right of the field and paused in center field, looks around and then runs off 3/4 to the right (or left if you wanted), we’ll be looking at what the character is doing. If this scene lasts 3 seconds, we don’t
There is only time to look at the character, see what they are doing and follow them off screen. You catch the background for about 1/4 of a second before the character is fully in field, registering that we are in an alley and there is a fire escape and a garbage can in the lower left foreground.
Sort out what the priority of the scene is and how you can exploit that priority to its fullest. If that means leaving out some minor details, then go ahead and do it. If the detailing is absolutely vital to the scene, then put it in.