Kathy settles her left hand in the crook of Don's arm when he offers it, then her right in Cosmo's arm when he offers, and the three of them trip off to lunch together. It won't appear suspicious or strange, Kathy reasons to herself; she's being escorted to lunch by her fiancé and his best friend, who is well-known as a jokester and a friend of Kathy's as well. It will all be fine.