First of all he put into his men and into his sergeant the fear of death.

But he did more than that.

He breathed into them something of his own spirit of invincible determination.

He had them springing at his snappy orders with an eagerness that was in itself the larger half of obedience, and as they obeyed they became conscious that they were working under the direction of a brain that had a perfected plan of action, and that held its details firmly in its grasp.
Not only did Duff show himself a master of organisation and control, but in a critical moment he himself leaped into the breach, and did the thing that balked his men.

Did a heavy transport wagon jamb at the gangway, holding up the traffic, with a spring, Duff was at the wheel.
A heave of his mighty shoulders, and the wagon went roaring down the gangway.