Maybe he is going after someone who won him in a contest to explore the land below. (Perhaps a rival.) He could have done this as result of jelousy or a prophetic dream.
I agree with Link-182. Also, when was the last time link got a nice hot mealwith a cold glass of water followed by a comfy bead? (He had a bead in MC last, and his last meal was in TWW.) (I do not count the stew from TP a meal.) And he has not had water since OoT. So sad.... Plus, he must be...