He couldn't, and Serph knew it.
Serph had looked at him straight in the face without a trace of fear. Instead, his eyes had been filled with condescension, glinting at him in dark humor, mocking him, daring him.
He hadn't trembled, showed any sign of weakness; the cool steel was held firm in his hand. Still Serph brushed off the threat with such ease that, if it were possible, he would have pulled the trigger simply out of spite.
But Serph was brilliant and knew more about the workings of his mind than he did himself.
Serph had quickly decided with confidence that he wouldn't be able do it. Observations suggested that despite his hatred, he would never rid himself of Serph's presence for some unknown reason.
Oh, but the look on Serph's face indicated to him that he knew. He always had.
He swallows dryly and takes a deep breath. His aim is right on Serph's heart. He tries to maintain a straight face, but the fact that Serph is smiling even more wickedly tells him that his mask is cracking. His breath is caught in his throat as he pulls the trigger and the loud, familiar cry of a gunshot sounds out.
Only Serph is still standing and it's him who's bloody in the chest.
He doesn't have to look over his shoulder to know who it is, the sound of Argilla's soft crying makes it more than obvious.
Serph watches him topple over, well aware that he is perfectly capable of firing for his entire journey to the ground. However, Serph doesn't move, he knows it's going to play out exactly how he'd imagined, because sometimes the human mind is so damned predictable.
He takes in a breath, and it is then that he finally recognizes the pain shooting like wildfire through his veins. The bullet probably missed the heart and hit an artery, he surmises, unsurprisingly detached about his own death.
He spends the last moments of his life trying to figure out why, of all things to feel at the time of his death-- betrayal, anger, and hate for starters-- does he feel relieved?
Serph slinks over to him, and as he kneels and grasps the gun still warm from his, now fading, body heat, his eyes smugly inform him that he knows the answer.