Just double checked and the basic explorer spell (Dungeon Walk) cannot be used during a fight, but the system only bonus spell Warp can, so technically he could've run away, but also doing that would expose his abnormal ability.Something in my mind is saying that somewhere in the manga is said that you can't teleport when there are enemies nearby, fighting you or something like that. But I'm not that sure.
There's a down arrow on that 'screen' of Durandal in Ch 1, implying that it has more skills than shown.Where did Ignore Defense and Ignore Level Gap Modifiers come from, they weren't there in Ch 1 when he first picked up the sword?
possibly it sounds better in Japanese... maybe“Die in ignorance” is so cringe to say out loud.