You may be 100% correct, but I'm not going to be the guy going, "Erm, actually..." after seeing that at 3 o'clock in the morning.

I’ve always wondered, what if I had broken both ankles or was unconscious?

at least here, they have a smaller, more "hurt the EMT's back"-y stretchers for those situations.

I dunno about where you are, but there's a few different methods for transporting patients who are not ambulatory:

Stair chair. It is a wheelchair type device with tracks on the back. You get to a flight if stairs, you fold the tracks out, and the patient leans back on about a 30-degree angle (not sure what that is in metric (that's a joke) sorry), and you basically slide down the stairs on the tracks. Great device for patients who can be in a seated position, like Tanner Hall.

Backboard. Everyone knows the backboard. Not great for stairs, but can be used in a pinch, especially if suspected c-spine or potential for hypotensive events.

Scoop. Scoop is a backboard is concave and splits apart down the center longitudinally. Great for folks who are down and cannot get up and cannot tolerate being moved; I.e., broken hip. You bring it to them, open it up like a scissor, come down, and close it around them. It does not touch in the middle so you don't need to worry about pinching. Downside is you'll need to use cravats to secure them, or use the scoop and put them direct on steetcher. Not ideal for going down stairs.

Reeves. It's a flexible stretcher. If you need to carry someone a long way with moderate ups and downs and lefts and rights, reeves is good. Have used it in tight homes, down half flights of stairs, and in the woods. Easy to clean for when people are bleeding or shit themselves. Lightweight. Really cradles the patient in there too, like a little cocoon.

That's all I got for now, but there's more, like high/low angle rescue. But for a broken ankle, I'd generally tell you to man up and hop down your stairs.

You'd be better off just mushing the bean and letting it decompose