Pills that won't stay still

I'm in a pharmacy where the shelves are empty, just rows of little glass dishes. On each dish is a single pill, but every time I reach for one, the scale next to it starts wobbling, and the pill rolls off and disappears into a crack in the floor. I keep trying to pick them up, but they keep vanishing. The only sound is the clicking of the foil blister packs I'm not touching.