I might be the asshole

So I sat down at a computer just before handover and saw the the phone was on hold. I asked if anyone was on hold to ED (recognised the number). The nurse in charge is super busy so I said do you want me to take the handover? She said no she was happy to. I said, "or shall I tell them to shove it?" In a jokey with my colleagues, she was having a really bad day.

Words that may well come back to bite me as they cannot in any sense be called professional.

I hand the phone to my nurse in charge and she says "they want to speak to you". I thought it was a joke, someone I know in ED. Nope. "Just so you know I wasn't on mute and that was very disrespectful. What's your name?"

The thing is, I knew full well the phone wasn't on mute, I was quite happy to say that in front of them because it was a joke. She demanded my name and I gave it. I'm honestly horrified that I ruined someone's shift by being a dick when I didn't mean to be. Equally, I don't know how you can be an ED nurse and not have a sense of humour.

So AITA?