Did anyone catch the prostitute refference?
When Jackson (the witness from the train) leaves Keyes' office, Keyes tells him that his secretary will take care for the expenses, so that Jackson can leave that very day.
Keyes: He'll take care of your expense account and your ticket for the train tonight.
Jackson: Tonight? Tomorrow morning would suit me better. There's a very good osteopath in town... I'd like to see before I leave.
Keyes: Osteopath? Well, just don't put her on the expense account.
... Them old movies with undercurrent messages