Dance of the Sugar Plum Pillbugs

In my early teens I had a potted Italian Stone Pine. Each December I'd bring it indoors to decorate. A mini Christmas tree for my bedroom. I strung it with lights (I liked the needle framed blotches of color they cast on the wall) and kept a plastic dish under it to collect the water.
One December, I woke up around three in the morning to a weird rustling noise- something you might hear if you ran your finger through a bowl of dry beans. What was in my room? I flipped on the lights.
The plastic water dish was filled with pillbugs. At least a half inch of them, crawling over each other and in circles. Grey ones, black ones, even a few brown ones. It seemed they had chosen the inside of the pot as a daytime hideout (they need a cool, dark place to breathe well). When it got dark, their explorations were thwarted by the steep sides of the dish.
A single pillbug on the sidewalk is cute. A living wreath of them at the base of my tree? Not cute!
What to do? Enough bug spray to kill them would pollute the room, and leave me with a pound of dead bugs to deal with. It was too awkward to take the tree outdoors with the dish intact... and what if they started climbing all over me?
I chose a sneak attack. Since they couldn't get out, I left them to run laps in the dish until dawn. They retreated to quarters. I took the tree outdoors and sprayed it the base of the pot. Either the squatters within died or escaped from the top, as I never saw them again.