Well that wasn't good. As soon as she heard the subtle click of the machine being powered on, River knew it meant trouble.

"Hold on, I'm coming," she said, with slightly less patience than she could have had, making her way carefully but quickly back toward the commotion.

Once she was close, her voice was slightly gentler, but there was a note of amusement as well, "I would suggest you keep moving until I turn it off."

When she was confident she had the right button and wasn't going to inadvertently kick the machine into a higher gear, she pushed it.

"Better?" She probably found this far funnier than he did. "That, dear, is a treadmill. Some people prefer to get their exercise indoors."