When you put the vault to the end of the scene. I personally believe it sort of takes from the feel you are going for.
Sort of like the ‘follow the light’.
I understand that you are intending on playing with the composition all together anyways… but in this case I think it would be a little bit harder to be able to show the guy tired from the back.
While dancing I remember this ballet that was over-talented… he would turn his back (Rule one… you never turn your back to the audience… thus the reason for the stirct ballet pozes) and you would be literally able to sence him crying in the stage without seeing his face.
This was an exceptionally hard thing to, and had managed to really get him to higher places.
I hope you can understand the point I am getting at…
If there is a story that expressions can only tell. You had better do your best you can manage to assure that it is understood exactly as you had wanted it to be.
I think I am getting the colour theme you are aiming for. And I think it would really go with the rest of it all. Do you have a mind to make the walls really warn out and producing hard contrast edges from the sharp light that the vault is generating?
I believe it’s going good Juha… But I guess the ‘everything’ is gona be more what revealed with your modeling. 
Curiouse on what you are up to. 
Black