Puddleglum and The Last Battle

I have previously made known my disappointment in Tirian the last King of Narnia, despite Alsan's tacit approval: (1) Tirian waited way too long to discover the truth of the arrival of Aslan. Immediately upon hearing of Aslan's arrival, he should have (minimally) sent reliable officers to verify the truth.  (2) Tirian rashly (as Lewis describes it) seeks to avenge the murdered dryad without a comprehensive (or any) plan. (3) This leads Tirian and Jewel to kill two unarmed Calormens (rightfully in my mind). (4) At that point Tirian effectively gives up, completely ignoring the possibility of repentance) and hands himself over the Shift and the Calormens. This is nothing short of a complete abdication of his duty as King of Narnia. 

However, there is a more fundamental question regarding the actions of Tirian and all of the Talking Beasts living in the north of Narnia. Why are they willing, without checking (!) to believe that Shift is Aslan's interpreter (even beyond the question of Shift's obvious character flaws)? Can they believe that Aslan would be willing to have such terrible deeds performed in his name? 

Ignored by Tirian is the theological charge of Puddleglum in the Silver Chair, "I’m going to live as like a Narnian as I can even if there isn’t any Narnia." Could a Narnian, based on everything known of Aslan, call Shift's command living like a Narnian? Is not the imaginary Narnia in which Narnians are free from human subjugation (as the old Bear argues for) so much more so much better than the Shift's version of Narnia? 

There are some challenges to this. God does indeed send His people into slavery, but to atone for their sins. And even in exile there is a need to 'Live like a Narnian,' to refuse to accept the world as is but to strive to create the world that Puddleglum perceives. God's chosen people may be slaves, exiled, discriminated against, but it's irrelevant if the people themselves refuse to believe it. 

This is lesson of the just observed holiday of Passover. Our Sages insist that the Children of Israel were redeemed early as they were in danger of complete assimilation...

This probably needs some further thought as well, but hopefully it's coherent enough...