Microwaves used in cooking appliances are designed to contain the radiation within a metal enclosure and have safety mechanisms to prevent operation when the door is open. The microwave energy is directed specifically towards the food, and the interior is designed to reflect and contain the microwaves.
If someone were to enter a microwave oven and it were somehow turned on, it would be an extremely hazardous situation. The microwaves would penetrate the person's body, causing rapid heating of tissues and potentially severe burns. Additionally, the enclosed space would lead to a lack of oxygen, which could quickly result in suffocation.
Microwaves should never be used as an upgraded sauna or for any purpose other than their intended use. It is crucial to prioritize safety and follow the manufacturer's guidelines and warnings when using microwave appliances or working with microwave equipment.