My father used to serve in the Russian strategic rocket forces in the 70s (the nukes basically, which, ironically, would then be pointed straight where I sit today in the US, since we have some decommissioned ICBM shafts straight in the middle of the neighborhood), and they did a much cruder version of these experiments for "fun". They'd kill rats by throwing them into the path of a particularly powerful and massive radar beam. I doubt rats felt comfortable or particularly non-anxious, however, seeing how they'd be dead before hitting the ground after that.