Time was all around. Burning, shining, tearing through his body as if his muscle and blood and skin and bone weren't even there. The colors alone could kill, not to mention the bone-crushing silence. Jack clung to the outside of the TARDIS, willing the Doctor to stop, to pull him inside, to do something. The sizzling, singing raw power of the Time Vortex wasn't meant for anyone to live through. He would have given anything to stop the sensations, but at the same time he never wanted it to end.
Jack thought that if anything could kill him and leave him dead once and for all, it would be this-