Microwave turns on when opening the door. Apparently this dangerous failure is common? Why is the safety mechanism so poorly designed?

My Black and Decker microwave began acting up in a very dangerous way.

With the microwave off, simply pushing the door open button to open the door causes the microwave to actually turn on while the door is wide open. Turn table going and microwaves blasting. This was reproduced multiple times. In one case my hand was close and I could instantly feel my hand heating up being cooked.

I was looking this up on line and heard a couple sources state this actually is not too uncommon of a problem due to an interlock switch failing.

I can't believe the safety switches are designed so poorly as to fail in such a manner, that it fails to the on state.

I could understand if every redundant switch got jammed and the microwave thought the door was still closed and chose to allow itself to still run. But this is on a whole different level where a microwave that is not even on with the door shut, decides to turn itself on the moment it is open. There should be multiple redundant switches and if those switches fail, then it fails to the off state. It should not be possible to fail to the on state.

I'm just baffled at this safety design. Is there any explanation why it is like this?

Edit - Actually, thanks to some of the commenters, after a little testing I no longer believe it was actually emitting microwaves, but rather it was just the light, fan, and turntable going, along with some residual heat escaping.

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