The saddest part about that end (and I think Philip subconsciously knows it) is that it is absolutely correct. Being lied to about everything (including your identity) by your parents would fucking destroy a child, especially if they found out around Paige's age. Elizabeth is so ideological (and hopeful that Paige will become just like her and validate her choices) that she'll blow right by it (as she did this whole episode [and series]), and Philip will initially reject it, but it'll gnaw away at him. When something horrible eventually happens to Pasha, it'll reflect on what the Jennings have done to their own children and it will land on Philip's face
I know it is a slow burn season, but I'm admiring how psychologically ugly it is getting.