Personally I would allow any player group to speak to Broyan and Kallyr, have them spot an assassin on a roof and let them take them down, Kallyr or Broyan would want to see who saved them. They may then even trust them to undertake a mission - defend the east gate, carry this message to Kallyr, guard these priests as they prepare the teleportation spells / summon air Elementals / open the hero portal...
One of the big issues with a lot of the old published scenarios is that players just get to watch, it's drab, it's dull and it's not fantasy. Remember Bilbo was a hobbit sitting at home, Belgarion was a stable boy and Arthur was a squire once, but they all became heroes not spectators.
Simon
Sent by me.