I agree with the latter statement, but only partially. To save your own hide as a thief you would have to do what it took. The thing is however, for a thief, being greedy and what not is acceptable, unless your sphere dictated otherwise. For a paladin to do that is not acceptable.

Also, from a goodie point of view, the life of a lightwalker is more important than any item, material thing. Going by that argument, you could say that he did the right thing.

Its like in war. Its acceptable for archers to flee from combat and save their hide if they can, but its not acceptable for noble troops such as royal knights, bodyguards etc, who have pledged their service and life to their lord. Thieves a different kind of animal, be they good or evil, they can never be really good. They hover in the almost good/neutral/evil zone. When you have pledged your service and life to defending the light, Fortress/Maran then go and die for your cause.