One of my Omake's being re-purposed as canon? Go for it!
I don't write much, and am honestly not that good at it (I would
never be able to write an original fiction, for example); but I am decent at short snippets when the muse strikes. This was one of the longest things I've ever written, and possibly the most coherent.

Out of curiosity, what bits of the range needed to be reworked?
I had envisioned her in middle of the waiting area, with her able to heal relatively effectively to around the edge of the waiting area, and able to sense things a bit further out; hence her needing to start moving towards the ambulance before the woman started stabilizing, and healing faster the closer she got, while not having enough control to have the metal rod removed until she was touching her.
The hospital staff were bringing patients to the waiting room to be healed, rather than her going to them -- and since she was in the ER receiving area, she'd obviously see all the critical patients right away -- and the patients sitting in the waiting room weren't waiting to get seen by a doctor, they were currently being treated. I imagine the people waiting to be treated in the waiting room were handled before she even finished introducing herself to the hospital staff, which emptied it out quite readily since everyone was healthy again.
The man with his arm in a sling around his arm just had a sprained muscle, so was healed very quickly since it was so minor.
If anything I was worried I had downplayed her range too much honestly, lol.
Also... Something I wrote not just being made into canon, but
changing canon... Wow.