And the collie merely waited his chance to get out.

At ten o'clock, one of the kennelmen made the night rounds.

He swung open the door of the little stall in which Lad had been locked for the night.

At least, he swung the door halfway open.

Lad swung it the rest of the way.
With a plunge, the collie charged out through the opening portal, ducked between the kennelman's legs, reached the open gate of the enclosure in two more springs; and vanished down the road into the darkness.
As soon as he felt the highway under his feet, Lad's nose drooped earthward; and he sniffed with all his might.