Arokhslair.net

In the catacombs, Rynn needs to jump across a moving floor. I made her jump to the left and after score of times, she made it( lucky jump ) [:D].

The guide says that rynn should jump in the middle of the room but I can;t see how because the edge is a lot higher.

She should catch the ledge when jumped from the middle if timed right however, this is difficult to do.

Here's the scoop if you haven't gotten across yet.
Just wait for the ground to stop shaking, save the game and jump from the middle, just like you said you heard. She'll grab onto the other side, and you'll hit triangle or up to get her to finish climbing up.
The key is waiting for the shaking to stop.

This is what I did

Slow time

As soon as Rynn reaches the middle of the steps, jump!

It's hard to do, but eventually she'll stick the landing.