Why does the oven door have to be open when broiling? Or does it?
When you briol food, you want the burner to stay ON. You’re counting on all that radiant heat coming from above the food, to sear the meat (for example). You don’t always have to leave the oven door open, but there are two reasons to do this: 1) The oven may reach the temperature associated with “broil” and turn off the element. 2) You may not what the entire piece of meat, or whatever food you’re cooking, to heat up. A baked alaska might be in this category. You want to get the top hot, without getting the insides hot, so you really want to keep the oven cooler than if you shut the door.
