Thanks, Jade and Pip.
We got Beau home around 6:45 last night: he held onto his urine all day, then when the vet tech tried palpating his bladder, had a hissy fit. We were sitting downstairs & heard him above, hissing, thump as he got away, then more hissing. The tech told us he peed on her, lol. She was very good about it.
Good news: no cysts, no giardia!