Jack was not weak.
While his domain focused entirely on escaping. It didn't mean he lacked firepower.
No, for most space based domains, firepower was never an issue nor was there a need to be on the defensive, as Jack was too hard to catch or attack.
But while fighting those undead necromorphs holding Thalia's power, he was hit hard by something unexpected.
Following which his body was filled with the power of destruction, making him weak and unable to conjure up his true strength or use his system.
Though, does this mean he was helpless against it?
Yes, at the start that is. But there is always a difference in the quality of domains and as it is, a weaker domain gets swallowed by a stronger one. So can happen with the power of destruction in his body, which was born from modified power of a grade four domain user.
