I challenged myself, as a new pilot, to go into the barn of Straw Bale in Liftoff.  I eventually made it in several times and always crashed trying to turn around to get back out.  Recently I accidentally landed after going in, then tried yawing while still on the ground to turn around and face the door to exit.  It actually worked, and I got out.  Is this a simulator quirk, or can actual drones do this... yaw to face a direction while not airborne?

It’s not a quirk, you can yaw on the ground irl.you can also slide forward and back and side to side, if you have enough prop clearance.

Edit- actually, I’ve never tried spinning in place. I’ll try tonight and get back to you. But I have changed my orientation on the ground.

You can turn around but you can get the quad bouncing if you’re not careful. It’s better to just hover and turn around but that’s going to take a little practice.

What Kevin said.
It’s certainly not a smooth turn- a tiny little bit of yaw and you can smoothly change direction, too much and it will start bouncing while spinning. I couldn’t get it to stop bouncing unless I either disarmed or gave it enough throttle to hover.

I'm trying to understand why it would bounce. Is there also a downward force while yawing?

"bouncing" is affected by the ground; not inflight situation. the flightcontroller tries to handle a flight situation, there isnt inflight situation, unwanted behaviors like bouncing happens.

airmode feature cause mutch more bounces, if you fly pure acromode without airmode feature, you would get less issues, "bounces"