He can't answer yes to either. If he admits to selling V, he'll face the True Death. If he blames Sophie-Ann, she will shoulder the punishment for the V, but he will be executed for having betrayed her.

And if he is gone, who will then protect Pam?

He knows that his silence is a damning as a wrong choice, but he can't -

And then Pam screams.

And yes. Yes, they can blame Compton. It is not ideal, but it will buy them time.

"It is true," he says, quickly.
"He - he is gone missing." A little hesitant at first, but warming to the story by the second.
"You've seen yourself how easily he betrays our kind for personal gain. I believe he is behind this, and I am gathering evidence to bring him to you."
Finally hitting that note of sincerity he has cultivated over centuries. Not looking at Pam because it will make him stumble. Trying to ignore the pain she is feeling. The anguish.

"Now let me finish my work."
Quietly insistent. Willing the Magister to believe him. To buy the lie.
To let Pam go.