So, we saw the burning building in Waukeen's Rest, and ran in to help the Flaming Fists break down the door on the second floor to rescue the person trapped up there. For some reason, as soon as we get in everything stops being urgent for a bit and there's a long dialog cut-scene, and then we need to rush out before suffocating, and then there's more talk and we're given the Rescue the Grand Duke quest.
Then, we went and did some other stuff, and learned about the Zhentarim hideout, so we went back, and found everything still on the same amount of fire (which is kind of weird, right? it was several days later!). When we got down into the basement where the door to the hideout is, Wyll had a "I want to talk to you" exclamation mark. I talked to him, and he has a long spiel about how the building was burning but we did nothing.
But, we did something! We helped!
I see in the wiki that there's another trapped person which we apparently didn't notice. Maybe that's it? But "we didn't rescue a person we've never heard of and didn't have any reason to look for, and actually in-game don't even know is there" doesn't seem like a good reason to trigger this sad speech.
