14529 - please throw me a bone

[arevn]

It's been years since I played MMaM and I'm having fun rediscovering it with the HD version. All was going well until the infamous library. 14529 is the room Jack enters up a long ladder and there is a green key out of reach. I am on the ground floor of the left side and have pulled the lever. Now, how do I get out of there? I have looked for ladders and vines and spent an inordinate amount of time jumping around hoping to find some ghost platforms. What am I missing?

Thanks!

Arevn