Easiest, non-luck-based way to get the “Call An Ambulance” achievement. No explosive rebar required! Requires Endless Abyss.
Menu
To start, go to the Endless Abyss mode. You’ll, of course, have to had beat the Abyss to get the endless version, but considering you’re here, trying to get a niche achievement that doesn’t even give you any benefits, rather than, y’know, beating the Abyss, I’m going to assume you’ve unlocked it.
Make sure the Survival Mode binding is on, and hit play.
Artifacts
The Endless Abyss starts with a Rho Altar offering two artifacts. The artifact we need is the spear to break our bones. Restart the mode until you get it.
Now that we have the spear, it’s time
Bone Breaking
We’ll be breaking the arms first, as jumping helps use the spear, but any order is fine. If you’ve used to spear before, you can skip most of this.

First, climb onto the pedestal. We’ll be boosting off of it for all of the bone breaking.
Now for the tricky part.

Throw the spear under yourself as you jump, boosting yourself up, before calling the spear back to yourself, sending yourself even higher.
(Also make sure to get rid of your spear before you fall all the way down to the pedestal, so you can grab the ledge with both your hands. I personally like to drop it, but you can put in your inventory if you like.)
Finally, grab the edge of the pedestal with both of your hands right before you hit the ground, breaking your arms in the process.
For the legs, do the same, except this time fall directly onto the floor instead of grabbing the pedestal.
Congrats
That probably hurt, didn’t it? But hey, at least you have the achievement now, and bragging rights a sense of accolmpishment.

Tips
If you launch yourself too high, you’ll die from the fall damage when you fracture your legs.
If you’re having a hard time getting on top of the pedestal due to your, well, shattered arms, or are about to die from the agony of breaking every bone in your body, there’s a can of beans in your inventory.