When exactly does retaliate trigger?
Retaliate triggers after all effects of an attack have been applied. If the retaliating figure dies from the attack, the retaliate does not trigger because the figure is removed from the board beforehand. If the retaliating figure is pushed out of the range of its retaliate, it also does not trigger. However, if it is pulled into retaliate range, it would trigger.
Since the Augment bonuses add effects to attacks and retaliate triggers after all attack effects, your Mindthief survives to fight another round!