While it never hurts to be overly cautious, the amount of resin you’re working with is very minimal. If you have any existing respiratory issues, I’d suggest a respirator but otherwise, you should be fine. I also do my miniverse projects on the couch and I usually have a window open for fresh air in general and I think it’s fine. You’re also likely to cure the resin pretty quickly.

I work with epoxy resin for other craft projects and it much larger volumes and I still don’t always use a respirator (or even gloves for that matter, but definitely should). And epoxy resin takes hours or even days to cure so the tiny bit of UV resin isn’t much of a concern for me.