While this looks to be a simple scene, with characters miles apart, I tried to give them some symbolic heft. On the left side of the page, as C arranges photos on his board, building his case, the images are meant to suggest that he is building a wall of bricks (the photos are brick-like) to entomb M on the right side of the page.
Similarly, as M stands in his office, the window panes look similar to a brick wall; the light through the window panes creates a motley pattern on his suit, and his cigarette smoke creates a foolscap on his head (a la Fortunato). I'm trying to suggest that C is now the entomber (is that a word?). And the final panel has M looking out of his catacomb he's been walled into. Or, if it looks more like a prison cell, that works, too. And there's that black X on him again that says "gotcha!"
Even the layout of the page is meant to be suggestive of bricks in a wall with its staggered panels.