I have now set up a little bee fountain inside the greenhouse because so many bees get inside and get confused on the way out. The bee on the dandelion was one such bee who became exhausted in the hottest part of the day and was just giving up. I put some water on a dandelion, and they crawled up on it and got their energy back. A few hours later, they were still resting, but then they perked up and enjoyed the heather bush I had put them on.
I think our agreement was that I save the life (even though my greenhouse was the threat), and then I can take some pictures.