To wonder what happened to this young woman

[Christmaslights70]

I was in hospital and there was a young woman opposite me. I spoke to her as I could see she was looking for a plug to charge her phone. About five minutes later the doctor came and put something on her finger I believe a heart rate monitor/blood pressure monitor. Then all of sudden the doctor said she needed to go to Resus. Aibu to wonder why she didn’t seem that unwell as had just been talking to me.

Maybe her oxygen saturation was low and whilst she was able to talk to you, maybe it's indicative of a health decline that needs urgent treatment to prevent an emergency.

It could be anything. She may have complex underlying health conditions that don't present themselves obviously to others.

How could any of us know? Are you concerned she had covid?
She’s probably been swabbed before coming in..?
There could be any number of reasons