Better forget it and turn in." He yawned again and turned over so that his back was toward Johnny, and that youth took the hint and departed to find blankets to spread for himself.

He was tired enough to lie down and sleepy enough to sleep, but he could not blandly forget about those bullets as Cliff advised.
There were several things he wanted to know before he would feel perfectly satisfied.
Since the Thunder Bird was not here, why should strangers be shot at?
Their only trouble would be with the guards along the boundary, when they tried to cross back from Mexico.

But they had not tried it yet.
The guards were still happily unaware of how they were going to worry later on, so why the shooting?
"Oh, well, thunder! They didn't hit me--so I should care.

If Cliff wants to set guards around this camp before there's anything to guard, that's his business.

Like paying me before I fly, I guess.