I think there is two things about that quest.
1) WHen you've killed all the radscorpions, you get some exp (you can note this from the message window) that are related with the quest.
2) After you have killed the radscorpions, talk to Torr again. I think this is needed to really complete the quest, not just kill the radscorpions, which one may think whegetting the message after last one is dead.
You don't have to kill the Duntons, but you can if you want, they are quite annoying guys


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"As we all know, holy men has born during Christmas...
Like mr. Holopainen over there!"
- Marco Hietala, the bass player of Nightwish