What are the technical difficulties in creating a maser capable of inducing the Havana syndrome?

No. Those are kill you properly dead power supplies. Serious internal tissue damage. No point trying CPR. He’s dead Jim.

The dangerous ultraviolet waves – UV C at below about 280 nm – are blocked by most glass and plastic. I know – it’s part of my business to find things that will transmit those rays. Unless your tube is made of fused silica, it’s almost certainly blocking the dangerous part of the ultraviolet.

(Of course, there are still effects from wavelengths longer than 290 but shorter than the visible, and many people advocate avoiding such wavelengths where possible. You can still get a suntan through window glass, after all. )

I’m a ham radio operator and some (usually older) hams refurbish and operate old tube radios and amplifiers. They have a saying you see on tshirts and stuff. “Real radios can kill you.”

My brother was a Radio Officer on ships back in the 70s. He has a scar on his hand from an RF spark that got him in the Radio room.

He also had to regularly clear dead seagulls from the RADAR scanner mast.