A friend of mine was in the military as a radar operator. When it got cold, they'd turn the beam TOWARDS themselves for a few seconds to warm up. That's a massive amount of microwaves they dosed themselves with with no apparent side effects. They used to haze rookies by pointing it at them and making them sweat until the figured out what was going on. I would not be amused.

As a cool aside, something they used to do in battle was to heat up a tree until it literally glowed. This was a much larger heat signature than they produced, so a heat-seeking missile would kill the tree, not them. Their equipment was so precise, they could cook a single bird out of the sky with it. Or see someone coming from 2 HOURS away (by truck). They were never in uniform unless a truck was heading towards them, and they had 2 hours to get into uniform. Hardly a mad scramble.