First one that moves has to buy the beer

Had an opportunity to see a pretty rare helicopter land today for refueling. They are currently battling another fire here in California in the Sequoia National Part which was started by a lightning strike. The Skycrane is probably my favorite helicopter. 4500 SHP of pure power, the turbines spinning up are something that sends chills up your spine. I just filmed this for my own amusement but noticed something very strange - the ground crew stood under the craft as it took off. Never seen that before! Why would you do that?