Here is a refresher on room description The door opens onto a huge rooms with many pillars and exits. The floor of this room is littered with the shards of thousands of bits of broken crockery. There doesn't seem to be any way to walk across without the bits crunching under foot. As you start to cro...
This leads to an empty room 20 feet high by 50 ' long (should just fit in that space). It was a long time ago, but on a previous delve, you killed a wraith who entered the corridor from here
The few time a gold coin hits the plate, it bounces off. If he keeps trying, he could probably get one to stay eventually (sort of like those games you play at a fair)