H.P.D. means Hotel Protective Department, which is the department of a large agency that looks after check bouncers and people who move out by the back stairs leaving unpaid bills and second-hand suitcases full of bricks.

H.P.D.指酒店保护部，这是一家大型机构的部门，负责照管支票保镖和从后楼梯搬出的人，留下未付的账单和装满砖头的二手手提箱。