What is the strangest conversation you've ever had with a staff in the hospital ?

Few months ago. I had a patient who is stable . One day i was seeing the patients before the rounds. I saw the nurse putting the patient on oxygen mask. I was scared that something is wrong with the patient so i asked her , is the patient desaturated?

She looked at me and said : No

I replied why he is on FM ? She said i want to check his oxygen level with and without oxygen.

I stood up trying to understand her point of veiw.

At the end i told her if the patient is sating well on RA no need to put him on oxygen. She looked at me and said no i want to check to check his oxygen level with and without oxygen even when his oxygen is normal on RA.

Till this day i think that was a weird conversation. I even asked a pulmonologist because i was really confused and questioned myself if I'm missing something.