It really builds off the scene in Warrior's Apprentice, when Miles is on trial for basically his loyalty to Gregor being in doubt. So we can see that by now, Gregor really understands and believes in Miles' loyalty.

It makes me want a book of Gregor's pov, set in these years - like when his advisors in Warrior's Apprentice start in on him, whispering things to lead him away from Aral's philosophies, etc. To see inside his head all this stuff with Miles and watch Gregor grow up and deal with all the stuff he's dealing with.