Luthen doesn’t trust the team that Bail has assembled to get her to Yavin 4 and believes there to be a mole on the inside. Despite the fact that Mon doesn’t currently trust him, he sends Cassian into the senate building undercover to make sure she makes it out without falling into Imperial custody.
Mon gives her speech despite the ISB’s best efforts otherwise and flees the senate chambers immediately. She is initially hesitant to follow Cassian, but after a member of Bail’s team outs themselves as ISB and tries to arrest Mon, she sticks by his side. After more than a few close calls, the two make it out and take refuge in Luthen’s Coruscant hideout, the same place that Cassian and Bix lived in during their time on the planet.
But even though Cassian and Luthen by extension are the ones who successfully liberated Mon from the senate and got her to safety, Rebel leaders want the Gold Squadron to deliver her to Yavin 4. They want her to record another speech and give her arrival a little more fanfare. This is where the Spectres of the Phoenix Squadron in Star Wars: Rebels come in.
We now know that the episode “Secret Cargo” picks up after Cassian and Mon have parted ways. Hera, Zeb, Ezra, and Chopper begin the episode trying to stay hidden amongst a debris field while waiting for the Gold Squadron, their original task being to help them refuel for what is presumably the rest of the journey to Yavin 4. Erskin is one of the Rebel officers that the team initially meets, which makes sense given how crucial he was to helping Cassian and Luthen get her to safety.
When an Imperial cruiser arrives and starts attacking, the Spectres soon learn that Mon Mothma herself is the Gold Squadron’s secret cargo. The Spectres and Gold Squadron escape that encounter, but they aren’t in the clear just yet. They fight against other Imperial forces on their journey to Dantooine, but in the end they are successful and get Mon to what is presumably her first stop on the way to Yavin. She makes another speech announcing that she’s leaving the senate to fight for the Republic, encouraging people to join her, and this kickstarts the formation of the Rebel Alliance as we know it.
While Andor does change a few things about how this all went down, it connects Cassian’s story to yet another important moment in the rebellion. Even though he may not be the one to get credit for it as the Rebel Alliance tries to distance itself from the more extreme cells like Luthen and Saw, Mon knows what he did to bring her to safety, and it adds new layers to their relationship in Rogue One. Even in its early days, it turns out that the Rebel Alliance was even more connected than we thought.
