When I biol noodles/pasta, I sometimes put a lid on the pan without any vent space. As a result, the water boils out, so I usually let it vent. When I take away the lid to see how the noodles are doing, they quickly hide all the bubbles they were making to boil the water out of the pan. I feel like I’m checking on little kids who are planning some trouble in secret and pretend nothing is happening when mom sticks her head in their rooms.