It all hinges on what Tom says to Lizzie at the end of her interrogation: "I'm one of the good guys. Reddington is not who he seems to be, and I can prove it."
Let's unpack this. Have we seen Tom do things that are not good? Let's take lying to Lizzie off the table, since Tom is apparently saying that his years-along intimate deception was for her own good. But we've also seen Tom do things to other people that are not good - like killing Jolene. Was that also for Lizzie's own good? Possibly, but it seems more likely that Tom killed Jolen for Tom's own good - because he didn't want that loose cannon out there, compromising whatever he had going on with Lizzie.
Tom's "proof" that he's a good guy and Reddington is not is in a bank box, he says, for which he gives Lizzie a key. The last scene and the coming attractions for next week show that Lizzie is indeed disturbed by what she sees. This does not necessarily prove that Tom is a good guy, but it does strongly suggest that Red is indeed not who he says he is. My guess is that both are true: Red has indeed deceived Lizzie about something very important, but Tom's deception was not done in the interest of helping or protecting Lizzie. The differential diagnosis is that Tom set up whatever was in the bank box as a failsafe to incriminate Red and disqualify him in Lizzie's mind as her protector. It will be interesting to see how this plays out in the episodes ahead, and whether we'll get any final closure on the Tom story this season.
One other point about episode 1.19. Lizzie understandably expresses how outraged she is about Tom wanting her to adopt a baby. But think about how much more powerful this story line would have been had Tom made Lizzie pregnant. I wonder if this occurred to the writers, but the limitations of network television obliged them to go in a tamer direction.
See also The Blacklist Debuts: Alias Meets Jay Z ... The Blacklist 1.2: Mysteries ... The Blacklist 1.3: Construction Site Heights ... The Blacklist 1.6: Truth and Enigma ... The Blacklist 1.7: Natural Immunity ... The Blacklist 1.8: The Father and the Husband ... The Blacklist 1.9: Field Transfusion ... The Blacklist 1.10: Those Words ... The Blacklist 1.11: Red's Retribution ... The Blacklist 1.12: The DNA Meister ... The Blacklist 1.13: Red Writ Large ... The Blacklist 1.15: The Husband's Other Shoe ... The Blacklist 1.16: True Colors
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