Because he is cheating on the person is going out to eat with .Derek and Addison seriously need to find a room .Derek needs to be truthful to both Addison and Meredith .None of the above choices .
Why should Derek not be alone with Addison ?
Maybe Addison did n't have anything to do with it at all . " Ca n't get you alone , " he murmurs , and his breathing just keeps getting heavier and Derek can feel his hard - on against his thigh , not that he minds , but he does have a surgery in half an hour . And then he has dinner plans . With Meredith .