“The impact,” Tarek says patiently, “blows all foreign objects at least one hundred microns away.”

“I can’t believe you’re explaining this,” says Ellen.

“We agree that the germs want to get it,” he reasons. “But germs are small, right? So their legs must be even smaller.”

“You’re disgusting!”

“Tiny, tiny legs! To cross that space, they’re going to need five and a half thousand milliseconds.”

“You eat food off–”

“So if you pick it up before that time expires, you’re golden.” He leans back, triumphant.

Ellen drops her head into her hands.

Later, she strangles him with a phone cord.