If the warden was afraid of dying they would have left after Ostagar since Duncan was not more there to force anything and many of the quests of DAO are by far more suicidal than the final battle fought without a DR.
This is a game so things are a little bit distorted in the sense that no matter what, you have to follow the script of the story.
Irl doesn't work that way in order to accomplish those types of feat your sense of self preservation must be softened a great deal.
I'm unable to understand this @Tidus or @thesuperdarkone2 persons because what they said does not have any logical coherence,if a statement like that is said by persons whom continue willingly to throw themselves in mission with low rate survival it is really incoherent.
Their rationale is built upon meta game mechanics because since it is a game they know the PC cannot die no matter what unless it is the Archdemon,that's why they are afraid of dying only for the Archdemon,In DAO they are able to calibrate the exactitude of success and failure and that's not human nor it is realistic.