[@MelonHead]

[i]Ahead was the small, rocky hill behind which lay the beast's lair. It wasn't going to go over the hill though, but around it. Just a couple hundred feet of difference, enough so that there would be more than a few good-sized trees in the mech's way before they got there. Every little bit counts. The monster, sensing that its pursuer had put on a massive burst of speed, went into full throttle itself. It could ignore the pain of its body until it was safe, for now all that mattered was the cold sanctuary of its skeletal throne. Sixty-six miles per hour, not too shabby in comparison to the peak seventy-five of a healthy cheetah in its prime. At least, when it could avoid the bullets, which slowed it considerably. The mech was gaining steadily. Still, the forest ahead and the bend of the hill would make up for lost distance. Each bullet was getting harder and harder to avoid though. It was getting clipped left and right. An ear gone in the blink of an eye. 
There goes a patch of skin. A rock dug up from a round smashing into the ground ahead thwacked it on the forehead. By the time it arrived, if it arrived, it would be in as bad a shape as it had been eight-hundred years ago during the death match it had against that ludicrous, teleporting elf. 

Blowing up the entrance would not work, the tunnels were narrow and went deep. The rock that surrounded them was dense with age. 
[/i]