I think ,,,,

I was in the kitchen washing some dishes, or maybe I had started peeling some potatoes. Kaylee had come in our back door and was taking off her snow boots and other attire, and started coughing. We were on the other side of the door and couldn't see her but could hear her, and then as soon as Thomas heard the coughing sound he said, " I think Kaylee's going to throw up!"

I guess he's just used to the coughing sound right before someone does -- luckily in this case that didn't happen.