Why Hank should have picked his way up that dangerous place was known only to himself.

Jack could form no theory to explain it.

But he did not forget the dispute of the three Indians in front of the break and the start which one of them made to follow the footsteps of the white man.

There must be some attraction in the canyon for them all.
Jack's dread was that Hazletine, despite his undoubted skill, would frighten Tozer and Motoza by his efforts to defeat their purpose, and drive them into slaying Fred and making off before they could be punished.

But the cowman had his own views, and it was too late to dissuade him.
Keeping in mind the warning of his friend to use all possible circumspection in his actions, Jack was so guarded that a full hour had passed when he once more reached the break in the canyon, which had already afforded them more than one interesting experience.
So far as he could judge, he was the only living person within miles.
The two Indians that had flitted across his field of vision were gone, and it was impossible to say what had become of Hazletine.