Why would the amount of water affect the speed of cooking a piece of meat

These results show that cooking temperature can modulate the speed of meat protein digestion, without affecting the efficiency of the small intestinal ... Each slice was weighed, bagged, and cooked in a water bath for 30 minutes at the selected core temperature (Exp. 1: 60, 75 or 95°C; Exp. 2: 75°C).