If you know what the hell you are doing, and MMM definitely does, there is no safety issue. So he has a portable beam? so? where is all the dangerous power?...
really? ya might wanna read the FCC OET bulletin 65
it clearly states the MINIMIN uncontrolled distance from a radiating antenna @ 27 MHZ is about 32 feet @ 1500 watts to comply with the ANSI power density MAXIMUM limit of .2 mW/cm\2.
the distance is an inverse function of power, anything above 1500 watts/more gain/ect decreases the min distance.
........... but, as a newby extra, you already knew that, right?