After falling in the water what did Rainsford do?

After falling in the water, Rainsford swam in the direction of the shots he'd heard.

Rainsford remembered the shots. They had come from the right, and doggedly he swam in that direction, swimming with slow, deliberate strokes, conserving his strength. For a seemingly endless time he fought the sea. He began to count his strokes; he could do possibly a hundred more and then--

Rainsford heard a sound. It came out of the darkness, a high screaming sound, the sound of an animal in an extremity of anguish and terror.

He did not recognize the animal that made the sound; he did not try to; with fresh vitality he swam toward the sound. He heard it again; then it was cut short by another noise, crisp, staccato.

"Pistol shot," muttered Rainsford, swimming on.