After his conversation with Bryan, Tom decided to leave his costume for later, since he didn't want to go through the stress of wearing it now and taking it off later to go get lunch for Lucy, and then wearing it again.
He had thought of asking Harry to send someone to deliver lunch to Lucy on his behalf, but he had decided against that since it would not only stir suspicion among the staff but would also defeat the purpose of the whole thing. It wouldn't make sense if Harry was to ask one of the staff to deliver lunch to Lucy and have them tell her that it was from her driver who was too busy with another lady to bring her lunch up to her.
