I'm no geologist, but 180C doesn't sound hot enough to make rock behave like plastic.

Ninja-edit: It looks like the temperature / pressure isn't so problematic because of rock moving around, but instead to do with cooling the drill bit (which you can imagine gets quite hot). If temperatures increase, cooling the bit becomes difficult, and at high-pressures, pumping the coolant around becomes very difficult.

Source: https://geekswipe.net/research/engineering/how-deep-can-we-d...