In Vietnam war days I worked on an airborne laser target designator system. The beam was infrared from a YAG laser which emitted 10 nanosecond pulses at something like 10 megawatts power. It was expanded to about 2 inches in diameter near the emitter, and at that size it produced an audible snapping sound when striking dry grass. One afternoon we were adjusting the boresight from the back dock of our building when I saw a crow sitting on a utility pole crossbar. The devil made me do it; I zeroed the beam on the crow and gave him a burst, expecting some kind of spectacular response. The old boy didn't pay a bit of attention. I presume his feathers were reflective enough that no heating took place.
Moral: For every weapon, countermeasures can be devised.
You're talking about PPP- Peak Pulse Power. 10 ns is too short of a pulse to heat H2O in a large body. Pulse repetition rate must be faster and the pulse width wider for this. Fire Control radar on some aircraft has this concept. You know TACAN that asks/recieves code of the day info. It transmits at only 300W PPP and goes many miles. No effect on you, right? The transition between pulse and nothing must be fast enough and slow enough in repitition to create heat (power) in your body. P = I^2*R where R is the resistance of your body. The pulses must create the I - the current through your body.