Captain Alyssa was about to make another telepathic snarky comment to Tat when Iris interrupted her verbally, speaking to the council. 

"Mr. President," she asked, "The Unity would like to ask if we, as one of the few peoples capable of interstellar and space exploration, would be asked to accompany you in your journey." 

Some of the Unity had asked if the Doctor would need protection during his journey from any manner of threat, and also came to the realization that if he did they were one of the only ones who could provide that protection.