... isn't that the point? We could all be figments of someone else's imagination.
I like that convo, and I always go to listen. I always get it after completing the Broken Circle. Don't have any saves ATM where I completed another mission first, so I can't check whether it is the Broken Circle or the first mission that triggers it.
Speaking of checking... The first check I made was with a nightmare solo mage, and I got two random encounters when I travelled away from Lake Calenhad and back, to see whether that would change anything. The thing with the wolf pack and the wolf traps that don't trap wolves, and then the Bereskarn thing. With a mage fresh out of Lothering. But I loved every second of it - Sonea trounced the opposition without even breaking a sweat.
Then I reloaded a save from my first character (which I had kept out of sentimentality). A dwarven noble shield warrior, who had gone to the Dalish first and then died the True Death at the hands of a revenant. Anyway, he was level 10, travelling with Leliana, Morrigan and Barkspawn. They got the Bereskarn encounter, which is one of the easier ones in any case. And then I typed runscript killallhostiles for the second time ever... They would have won in the end, but it would have taken some doing, probably involving the odd pull from a bottle or two. I just couldn't make myself go through with it. It's amazing how much more powerful even a level 8 mage Warden is compared to a full level 10 party without one.