"The third kind are emergency cells and they seem to be more scattered and less predictable in location and number. They are because the queen was killed or lost somehow."
Random because the bees build them where ever they find larva the right age to make a queen. Which when a queen fails she lays less eggs in a random pattern. These queens are usually infeior to those of the other two types, and are a last resort for the bees to make a queen.
"I reject your reality, and substitute my own." Adam Savage