Depending on just how strictly you want to adhere to the theme, I think super reflexes, willpower, or even energy aura, could work, (the latter representing a sort of "psi shield" that your character projects or generates around themselves). Energy aura, in particular, includes a self heal and an end recovery power, which are quite nice. Willpower is more about being passively tough, in that there aren't any powers you need to actively click to use - you kind of just toggle stuff on, and get additional regen, recovery, damage resistance, and defense. Super reflexes is basically all about avoiding damage, but it has little in the way of recovering your health, should you get injured. It's a matter of how active you want to be in your play style, and whether you want to pour everything into avoiding damage, have a layered approach to damage mitigation, or have tools you have to actively use to keep yourself in the fight.