Your personal Tumblr journey starts here
It hurts me to think that Cale's worst fear is not his family and people dying, but being the only one to survive again.
That's what I think the reason Cale is so ready to throw himself into danger is, because if he does, not only will he potentially save everyone, but he has a high chance of not being left behind again.
His hyungs died protecting him, and he had to live with the guilt afterwards. The thought of going through that, technically for the third time, is what pushes him to overuse his powers constantly. It's why he was able to complete the Thief's test the way he did, even though it'something he managed to stop himself from doing during his life as KRS.
His fear is not the fear of losing everyone, but the fear that he will be the only one left alive.