His chest was a battlefield. Logic v.s Fear. His chest tightened with every step that he let mark Walk from. His body a rickashay of bullets. Rattled by Marks earthquake steps. Silence is more defining than Erwin Screams. More sharp that a knife carving his skeleton by its joints. 
I could say his heart screamed and Rammed for Ollie to spill everything. I could say his life felt meaningless without Mark. I could say, I could say, I could say so many things that it'd turn to a list of Metaphors for a broken heart. 
So many of us share this feeling of despair and a list of metaphors that all mean this meaningless idea of hearts shattering in our own cages.