Again, the battery is inches away from the lips and jaw. Something else happened than what was described as the initiating event. Glycol and Glycerin are not explosive and are normally used as food additives.
I am wondering if he wasn’t trying to vape alcohol, but even that should not have split his jaw and shattered his teeth. Burned his lips and mouth, yeah, that I can see, but splitting the jaw? What could do that? One thing might be holding a high powered gun too close and getting hit by the recoil when he fired it.
Why were the upper incisors broken? They are certainly weaker teeth than the jaw below? If he were gripping the mouthpiece of the e-cigarette with both upper and lower teeth, then certainly both should have been broken. Why was the force transmitted only downward? Strange.