Cigarette
When the restaurant staff went into Lucas' office to take what they were expecting to be empty plates, ended up with them taking back food that had been transported, cooked and delivered steaming hot. Even the way they had placed the cutlery was exactly the same showing that he had not even tasted the food.
When one of them wanted to ask him if he did not like the food, he made eye contact with David and remembered the warning they had received before entering the office, so he just kept quiet and proceeded with packing up everything before silently leaving.
David also wanted to be as inconspicuous as possible, so he did not say a word and also silently left with the staff.
Once they left the office, the one that had wanted to speak up couldn't resist but ask David.
"Did he not like the food?" the man asked.