Izaya took a step back. With Saki safe Izaya's fear receded and transitioned into something else. He realized that he was actually offended at this. It was ridiculous but there it was.
"Who else could I possibly be? I am Orihara Izaya."
Shizuo seemed to muse.
"Maybe it's some sort of trick..."
"Ah, that is exactly what it was. A trick and you fell for it."
But Shizuo was not convinced.
"I don't believe it."
"Why not, Shizu-chan? It wouldn't be the first time I pulled the wool over your eyes."
"Yeah but you don't put your ass on the line. Something's weird."
Izaya was becoming increasingly nervous. As if on cue Tom turned a corner and arrived on site, his step leisurely enough. He was used to following Shizuo's trail of destruction and knew by now that it was best to keep a distance until Shizuo's anger wound up.
"Shizuo, are you done? We have to get back, oh Orihara-san."
It was the distraction Izaya so desperately needed. In the time it took Shizu to look at Tom, Izaya spun on his heels and sprinted, turned into an alley and disappeared. Even after he was well out of the danger zone he kept running. He felt that his cover had been blown and that disaster was impending. It was by sheer force of will that he brought himself to stop and he had to lean against a wall to catch his breath. Izaya composed himself, emerged from the dimness of the narrow alley into the day.
Izaya was surprised to realize how much he had run. He was in a different part of town and needed to scramble for a sense of direction. Disorientation washed over him but he did not want to use the GPS service lest he ended up too dependant on machines. To a city creature as Izaya geography needed to become part of his inner mapping. He even avoided looking at any signs until he had some idea of where he was.
He walked into café, splashed cold water on his face in the restroom and drank some juice. His hands trembled slightly. As he was now he could hardly face Saki at all and for an alarming moment he needed to call Shiki. Izaya waited until it faded into mere wanting. He understood that he had to be alone and think through his tumultuous confusion. There are things that only he could sort out and this was one of these.
Having reached that resolution he remained at a loss. Shizuo's words resounded in his mind and forced Izaya to reflect on his own action. Memory loss or not, Izaya knew himself to be very driven to survive and not the kind to risk his life for the sake of others. Yet he had done just that. It did not occur to Izaya that he was becoming a better person but simply that he was becoming a different one. He caught a glimmer from his new ring and turned it over, holding the metal as if it was a delicate treasure. And then realized that it was precisely that.
He turned his thoughts to Shizuo now, reluctantly. His latent memory, or shadow of a memory, was stirred. He did not need to rely on the information he had acquired second hand through Namie and files to know that Shizuo had played an important part in his life as the embodiment of all that opposed him. It was painful that strive as he might to hunt for a glimpse of a memory regarding Shiki, he failed but Shizuo had imprinted his presence into Izaya's, somehow.
It made Izaya wonder if Shizuo was not connected with his amnesia. Angles to explore were Izaya's professional saving grace. Even if he was mistaken it would not be a loss of time. For one, it would put his fear into perspective since he would have to tackle it head first. And second, it was better to pursue something than simply wait for his memory to return of its own accord. Investigating Shizuo would take much careful plotting and Izaya was eager to devote himself to it.
To past grievances he knew of and the general feeling of antagonism that he could not escape Izaya added the fact that Shizuo had ruined his birthday and Saki's outing. It was absolutely unforgivable. If wishing someone dead could have an effect then Shizuo would have died. And there was more to it, Izaya blamed Shizuo for forcing him to acknowledge some disturbing changes in himself.