The weakened Railroad needs an edge over the Institute. This can come in the form of Patriot, their covert Institute contact. Unfortunately, they've only been able to receive messages from him and couldn't send any out. It is up to the Sole Survivor to arrange that...
Upload encrypted message on any Institute terminal
Desdemona gave me an encoded holotape that I can use at any Institute terminal to make contact with the Railroad's guardian angel, Patriot. Perhaps with him (or her) we can devise a way to rescue many synths.
Read Patriot's reply
Tinker Tom's encoded holotape worked. I sent an encrypted message to Patriot and received a message back: "Meet at the Advanced Systems maintenance room."
I've met Patriot, Liam Binet. He's eager to rescue a lot of Synths at once. But in order to do that we'll need help. I should follow Liam to meet his accomplice.
Talk to Desdemona
Patriot has a plan to rescue 13 Synths at once. But he needs login credentials for CIT's original security system, Code Defender, to do so. I should contact Desdemona to find them.