How we cite our quotes: (Chapter.Paragraph)
Quote #4
"You thought, as a boy, that a mage is one who can do anything. So I thought, once. So did we all. And the truth is that as a man's real power grows and his knowledge widens, ever the way he can follow grows narrower: until at last he chooses nothing, but does only and wholly what he must do ... " (4.106)
This is the Master Summoner talking to Ged about the limits on their choices. Now, this is only one character talking – and, remember, characters can be wrong – but what Master Summoner says here about the limitations of choice seems to fit in with the rest of the book. That is, Ged has fewer options precisely because he's so powerful and therefore has big responsibilities.
Quote #5
Hearing the mother's wail, and seeing the trust Pechvarry had in him, Ged did not know how he could disappoint them. (5.19)
Here, Ged feels like he can't make a choice, not just because of his power and duties, but because of his friendship with Pechvarry. Now, Ged does this thing for Pechvarry's friendship, but it's not actually the right thing for Ged to do – because Ioethe is too far gone, Ged should let him go. That's the duty that the Master Herbal taught him.
Quote #6
All night he tried to choose his way, to plan where he should go, what he should do: but each choice, each plan was blocked by a foreboding of doom. (6.21)
Facing the doom of the shadow monster, Ged feels as if he can't choose any direction. With the benefit of hindsight, we could say that the problem is that Ged is overlooking the right choice – he has to hunt the shadow, not run away from it. As in other situations, there's one right choice, which must feel to the character as if there's no choice at all.