And then, as he moved closer to the door, he caught a laugh, low, but clear and musical.
It was Betty's! He had heard it often when she had been talking to Dade; she had never laughed in that voice when talking to him! He halted in his approach toward the door, watching the light under it, listening intently, afflicted with indecision.

At first he felt only a natural curiosity over the situation, but as he continued to stand there he began to feel a growing desire to know who Betty was talking to.

To be sure, Betty had a right to talk to whom she pleased, but this talk behind a barred door had an appearance of secrecy.

And since he knew of no occasion for secrecy, the thing took on an element of mystery which irritated him.

He smiled grimly in the darkness, and with infinite care sat down on the floor and removed his boots.