He's always been a methodical man, thinking hard before speaking or taking action. So he takes in the Doctor's statement and gives it careful consideration. It just happens to be slower in the process now than in days before he was poisoned. The Doctor is not incorrect in his assessment now that Aleron gives it some solid thought and is enjoying a moment of almost lucidity. The days where the song doesn't seem so loud and looming are the ones where it is easier to block out the searing pain of the tainted lyrium in his veins. There is a slow nod of dawning understanding.

There is a moment, small and fleeting, where his mind wants to retreat back in on itself, somewhere safe and familiar. Thoughts that trailed to the blessed silence of the Vigil where there was nothing and no one present but himself and his commitment to his devotion. That solitude was tranquil, peaceful, and he rather aches to flee to a place like it again.

The temptation comes and goes and he returns his focus firmly back on the Doctor, lest it stray elsewhere and stay lost. "Let you... what?"

Aleron's bulwark of stoicism is eroding alongside his sanity and he actually looks mutually suspicious and curious. Mostly suspicious, by part his nature and by greater measure, the result of the torment he's been put to the last three years. But cool detachment is long since gone and it shows in his expression.