It's been said that there is given to every man a space of time to abide on this earth; that at the beginning of his life, the end of his life has already been established. That it is not a matter of when, but of how and where.
He is in the prime of his youth, and there is a certain bold confidence about him; although he respects death, he doesn't fear it. After all, more than once he's slid the edge of his sword along the edge of death's own blade, and has come away unscathed. He's been thrice shipwrecked, stared down undead pirates, escaped from the very ship that ferries the dead, has twice evaded the kraken's embrace.
And yet, his time is more limited than he knows. The boundries of his existence are shrinking. The edges of his life are being filled in faster than he realizes.
For something that had been slumbering all this time shook itself awake that day in Tia Dalma's hut.
"You," she spoke in a sugary twang as she stood momentarily transfixed by him. The obeah stared at him over Jack's shoulder, her eyes filled with some dark, secret knowledge. "Dere is a touch of destiny about you ... William Turner."
There is an unrelenting urgency that he feels now. He is restless, driven. He thinks that it is because of the threat of Bootstrap being absorbed into the Dutchman's embrace, like Wyvern. Part of the crew, part of the ship. The image never ceases to haunt him. He thinks that time is running out for his father, and saving him from his fate has become of chief importance.
What his waking self doesn't know ... but the deepest, most elemental places of his soul now understand ... is that he is running out of time for himself.