He doesn't answer. Speech distracts from action, and it should become obvious in a moment.

Success. Bounding from coil to coil, he leads its head in a circle until the neck can twist no farther and he is close enough to scramble up the dorsal ridge - crouch atop its head while it rears in surprise, brace himself between scaly crests, take a two-handed grip on his sword, and stab the wurm's eye as precisely and forcefully as he can manage.

He is perfect. He is not lucky. Though he drives the full length of his sword into its eye, it is not enough; the monster is not slain. And a moment later, its violent thrashings dislodge him from his perch.