|If a microwave oven door were to open while it was still on, what would happen? Could it hurt you? - JP
The microwaves would flow out of the oven's cooking chamber like light streaming out of a brightly illuminated mirrored box. If you were nearby, some of those microwaves would pass through you and your body would absorb some of them during their passage. This absorption would heat your tissue so that you would feel the warmth. In parts of your body that have rapid blood circulation, that heat would be distributed quickly to the rest of your body and you probably wouldn't suffer any rapid injuries. But in parts of your body that don't have good blood flow, such as the corneas of your eyes, tissue could heat quickly enough to be permanently damaged. In any case, you'd probably feel the warmth and realize that something was wrong before you suffered any substantial permanent injuries.