The absolute reveal is so baffling to me. The first time I saw those books explain the absolute, I was actually excited. I thought "whoa, if they're revealing this here, what else are they going to reveal later?" Only, there wasn't anyother twist. Why include those books at all? Why utterly ruin your twist like that for no reason?
Gale might have died up to a dozen times by the time you reach act 3. Especially with Withers, dieing is no big deal for you, so neither would blowing up be for Gale.
And even if you want to ignore Withers, its explicitly shown that Gale owns a True Ressurection scroll, so coming back to live after the explosion is possible.
Just another failure of Larians storytelling.
The orb is described as being able to destroy an area the size of a small city if it explodes. So if Gale explodes, there won't be anyone around to revive him, and frankly, the scroll probably gets destroyed in the explosion too.