Mrs. Wynnes stayed calm when the snake crawled across her foot under the table. This is ironic because the colonel and a young girl were just arguing over whether women are courageous and brave or not. She proved that women are brave and calm under these situations.
When the American got rid of the cobra, he was given credit for being the most calm in this situation. But the person who was the bravest was really Mrs. Wynnes. She felt the cobra crawl across her foot and stayed extremely calm under the pressure. She had the servant bring the milk and then told the American what happened at the end. He and everyone there were extremely surprised at what she accomplished.
The theme is that gender does not decide how brave, calm, or courageous that you can be. It only matters that people are brave and are calm in serious situations. This is shown when Mrs. Wynnes noticed the snake first, but didn't tell anyone. She even felt it crawl across her foot and barely flinched. That was a very serious situation that she took care of with ease.