In my world most magic is learned through hard work and dedication, and is mostly useless for healing. However, there are a very rare number of individuals who can wield some of the most powerful magic without studying, for now call them sorcerers since I haven't given them a good title yet (really need to figure that out soon).
Ignoring for now certain genetic/environmental factors required to become a sorcerer one of the most significant aspects of their magic is that sorcerers gain their power based on having a single defining belief or cause that they are so passionate and driven about that it fuels a sort of emotion/dedication powered magic. This means they can wield powerful magics, but only when those magics are used towards furthering those ideals or dedications that motivate the sorcerer and fuel his/her magic. This also means any sorcerer will, practically by definition, be so passionate about their cause that they are willing to make significant sacrifices for it; if they aren't that passionate they wouldn't have become a sorcerer!
I want to have one sorcerer play a minor role in my story. Originally using his appearance early in the story to justify an info dump about what a sorcerer is in preparation for a latter reveal of a different villainous sorcerer (he has some other minor roles in the story, but none too relevant here). I've decided to make the good sorcerer's passion about stopping pain and healing anyone in need, giving him access to healing magic that is otherwise not possible with traditional magic. However, since his drive is so much about not causing pain and healing anyone, including the guilty, he can't join our heroes to deus ex machina a solution to the villain. Actively setting out to fight, and potentially hurt, another person, even a villainous one, goes against his passion and thus he wouldn't be able to use any magic to aid in such a fight.
I had a nice discussion already played out in my head for how our good sorcerer/healer ends up info dumping some details about what a sorcerer is and setting up some later plot points, but this discussion can only play out if he has time to talk and joke with our protagonists. My problem is I've created someone who is the sole healer in a large city-state who is pretty much given to being willing to never take a break from healing when others are in need (he wouldn't be a sorcerer if he wasn't that passionate!). It's hard to believe that in a large city-state there wouldn't always be someone else in need of his help. So how can I justify his wasting time on a decent length conversation and joking with random protagonists who stopped in for quick healing when there should always be someone else in need of his help next?