If you ask me, Lujon can do anything - nothing ever proved otherwise. In my post - the extremely long one - I wrote that Lujon made a portal to the Heavens from the street in Luithen, and thus left Gyro alone. However, you ignored this in your post, and wrote something that he was in the Hall of Light. I accepted that, but that still doesn't change the fact that he teleported away from Gyro

Or... well, he could technically just have run away from him. Alright, fine, Lujon can't make portals. I'll edit it. However, remember that you might have plans for him, but so do I! He's my character as much as he's your character, and I am honestly trying to turn him into some all-powerful dude, like vKael ^^
Am'ar tries to get back the halo, because then Lizzie returns to her normal condition.
However, if they cannot get back the halo in time, Lizzie's soul will become trapped as a servant of the God of Darkness. Lujon said that, and that is why he does not like the whole idea about getting the halo.
Lujon instead wants to bring her to the God of Light. The God of Light can keep her alive in the Heavens even without her halo, and prevent her from becoming a slave to Darkness. However, without her halo she will not be able to leave the Heavens ever again.
Lujon doesn't care about the feelings of Am'ar and Lizzie. He only wants to prevent Lizzie's soul from becoming a slave of Darkness, because he knows that Fallen Angels are the most powerful servants of Darkness.
Am'ar of course wants to bring her back to her normal condition, but if he can't get the halo in time, he would much rather trap her in the Heavens and save her from an eternity in Darkness.
EDIT: Here's the edited version of Lujon's line. I deleted the part about him making portals, and wrote something else instead. Better?
Lujon said:
"Well... I'm definitely not on the mortal's side.. To be honest, I find you mortals utterly stupid - your idiot friend decided to use the wounded angel's energy on making a portal, which only gives us less time to regain the halo. Who knows - maybe time has already run out - maybe the angel has already fallen to Darkness because of your friend... And what about you, orc? You come here, believing you can defeat a Goddess and take back the halo... and you have only brought a Solar Guard's sword as your weapon and a shield as protection... Why am I even wasting my time helping such foolish beings?"