The bottom left of this picture shows a place you can jump to in the tutorial:
If you jump down there, you can't get out.
I would suggest a barrel down there. With iron leggings in it (unless those are already hiding somewhere I haven't found them).
You get where I am in that picture by jumping from the iron helmet parkour platform. It looked unescapable, but I jumped into it to see if the iron leggings might be down there.
Of course, right after I posted this I realized that you can probably get there (to the hole, not to where I'm standing in the picture) via another non-obvious route, too.
The bottom left of this picture shows a place you can jump to in the tutorial:
If you jump down there, you can't get out.
I would suggest a barrel down there. With iron leggings in it (unless those are already hiding somewhere I haven't found them).
You get where I am in that picture by jumping from the iron helmet parkour platform. It looked unescapable, but I jumped into it to see if the iron leggings might be down there.