He can sense Rassilon disapproving of the plan - whatever battles Shayde has to fight, he fights them alone, and with no will, that makes him next to useless should a fight erupt... but no one need know this. Shayde accepts this.
The tower is surprisingly easy to pilot back to Gallifrey in Shayde's home era. Of course, his simulated nerve endings and simulated Doctor-body feel pain, but Shayde's shuts that out, and concentrates on his work.
When he arrives, he shatters the glass, and allows the Matrix Personality print to do it's work. The simulated Doctor stumbles and falls, and speaks to Izzy. Oddly, and Shayde is not certain of this, but a small part of him that is literally just him feels sorrow for Izzy. Her Doctor is, in one sense, about to die. What an odd thought though; Time Lords invented regeneration to stop death. That's its sole purpose. Perhaps the Doctor has developed a different attitude.
The simulated regeneration is also a real one in a sense; the energy discharge is partially healing Shayde from the traumas sustained in transit to his form, allowing him to rest.
In the TARDIS, the other Doctor - the real one - approaches him briefly while Izzy and Fey are away and he is drinking tea. Lapsang Suchong, a very good tea. Excellent tea, in fact. The Doctor tells Shayde the plan. Then he looks Shayde over.
"Bald?" he asks.
"There's nothing wrong with a receding hairline," Shayde's Doctor persona replies. "Its most likely a reaction against your head of hair; now there's a case needing a pair of scissors if ever I saw one!"
For a moment, the Doctor seems stunned and angry by this outburst, but then he smiles.
"You know," he says, "you almost make a better Doctor than I do."
Shayde smiles, though the Doctor part of him feels like this is stating the obvious.
"Though I'm not certain about that bow tie," the Real Doctor adds.
"Bow ties are..." Shayde's "Doctor" persona struggles for a moment, then smiles. "Cool."
"Cool?" the Doctor asks.
"Yes, cool," Shayde says. "You'll think so one day."
"Rassilon forbid," the Doctor says. Then, suddenly, something judders, the Doctor slips out of sight and the Shayde/Doctor's memories and he's back to being the Doctor.
Every word he says, he hopes the Doctor would approve of. He intends to share the memories of today with the Doctor if he is spared. Submit himself for review.
Maybe Rassilon will let him go again, and this time, Shayde knows precisely what he wants to do; stop being faceless. In the back of his mind, he knows he is fond of this new face. The little suit he wears and the outfit he adopted is all something that he alone has created. The actual Ninth Doctor is going to be someone quite different, Shayde guesses.
When the time comes to discard the disguise, Shayde is sad. Shayde's Doctor is a persona he has become quite fond of over the course of this adventure. Still, he knows his duty.
He is downcast when he realises that his weaponry is useless against the Pariah. Eventually, he realises he is going to be destroyed. He thinks about what he will miss. The Doctor, yes. Existing, and having purpose, yes.
And, oddly, he finds himself missing Lapsang Suchong.
And then he is spared.
It is a long lifetime - many years - that he stays with Fey de Truscott Sade. Her span is long, longer still than it should be because he is making it so. Eventually though, Fey ages and Rassilon, needing an agent, separates them without killing her.
He doesn't know what to make of the Time War. It is a nasty little war, that turns into a nasty big war. Eventually, Rassilon restores himself... and goes slightly mad. Shayde finds himself unbeholden, unwatched, uncared for.
It is a simple matter to steal a TARDIS, tell it what to look like and then break the chameleon circuit. It is a simpler matter to change bak into the long missed form.
It is a much harder matter to find Lapsang Suchong tea.