When we put something in an oven, we are cooking in reality 3 ways 1. By conduction 2,By convection and 3. By radiation this is heat in transit it comes from a hot source and is converted back to heat when it is absorbed by other matter. So I believe even though the braising liquid is 212 at a max and creates a self basting medium the liquid does not cover the meat therefore the temp that oven is set for also cooks the meat. If you put thermometer in the potroast even though the liquid is 212 the internal temp will be much higher.
