why another crew member isn't used?
When you are out in the bush fighting fires, there is no capacity for carrying another person in the aircraft - otherwise you are dropping 90kg less water. And when you are directed to go to another fire, and then refuel at a bunch of drums sitting there by themselves, you aren't able to get your ground crew to gallop over to this new place to pump your fuel for you.
Every second counts in a fire. Our country had its worst ever rolling series of fires in 2019/2020, so when you are out of gas, you plop down next to the drums, roll down to idle and start pumping. When full of fuel, empty your bladder on the skid, get back in and go to work.
Yes I hear your little safety alarm going off, but it can be done effectively.
Airmanship is defined as the safe and efficient use of an aircraft, both in the air, and on the ground.
Sometimes, being safe means being largely inefficient, but being efficient (in this case) isn't as unsafe as you paint it to be.