They've been exposed to the outside world, up close and personal. They've had that fear planted in them. And they've endured it. Overcome it. Each has grown from that experience... and forgotten how to hesitate.
The slight difference between those who always aim for the top and those who don't... It'll come to matter in a big way once you all emerge into society.
Heroes and villains both thrive on violence, but we're still categorized. "You're good." "You're evil." That's how it is!! Symbol of peace? Hah!! In the end you're just a tool for violence, made to keep us down! And violence only breeds more violence.
If you feel yourself hitting up against your limit remember for what cause you clench your fists... remember why you started down this path, and let that memory carry you beyond your limit.