Steven Universe - Gem Drill...?

Peridot mentions some of the drill's specifications " will need to withstand up to 360 gigapascals of pressure and temperatures up to 9,800 degrees."
That does sound like a lot of work for Sardonyx to do alone, plus they need to have Peridot with them to help disable the cluster… otherwise they could've just locked her up as soon as she told them where it was.