This is a good question and there is a real practical answer. The tomb is not in a Pyramid but deep in a mountain reachable by a narrow stairway. You'd have to cut away or dig through the mountain to come close enough for a metal detector.

Or just stand on the other side of the wall?

I genuinely wish there was a magical way to just disassemble the whole pyramid and put it back together without any damage.

There is no pyramid, he is buried in a mountain.

Thanks

The balancing act between Egyptian tourism mystery golden goose eggs, and just cutting the pyramid in half.