Would you explain the using "or" like that way?

I saw the topic below. Then , I need to know the usage of the underlined, "or" in that sentence.
Would you explain the using "or" like that way?

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Joey: All right!! Okay, it was like four years ago. Okay, Ginger and I had gone out a few times, and then this one weekend, we went up to her Dad’s cabin. Just me, her, and her annoying little dog Pepper. Well that night, I cooked this really romantic dinner....

Monica: You gave her food poisoning!?

Joey: I wish. No. After dinner, me, her, and Pepper all fell asleep in front of the fire. Well I woke up
in the middle of the night and I saw that the fire was dying out. So, I picked up a log and threw it on. Or, at least what I thought was a log.

Phoebe: Oh my God!! You threw Pepper on the fire!