You haven't figured out the principle of the induction cooker upstairs. The induction cooker makes the bottom of the iron pot form a vortex through the changing magnetic field, thus vibrating and heating the food. It is estimated that the landlord is talking about the microwave oven, which makes the molecules in the food vibrate to generate heat. After use, there will still be radiation residue on the inner wall metal, but as long as you don't sleep with the stove, you will be fine. Also, the induction cooker itself will not produce radiation when used, so there is no problem. If you have metal objects on you, you'd better take them off.