The ground I'm walking on collapses underneath me!

Hint 1 of 9:

There's nothing you can do to stop that.

Hint 2 of 9:

All you can do is try to survive the experience.

Hint 3 of 9:

Not all of the ground will collapse -- the part near the walls stays put.

Hint 4 of 9:

Walk along that edge of the area, and you should survive.

Hint 5 of 9:

Now that the ground has collapsed, look around to see what's happened.

Hint 6 of 9:

Notice those wooden stakes in the walls of the newly-formed canyon?

Hint 7 of 9:

They seem to be pretty regularly spaced.

Hint 8 of 9:

Like steps.

Hint 9 of 9:

Jump down them to reach the bottom of the canyon.