Being dismissed to go eat, Oliver simply headed to the cafeteria so to see what bullshit they were going to feed them. Roxy said that the better you perform, the better you eat but Oliver was not trusting. How did he know that they wouldn't shit him over? there's no telling but to find out first hand. Simply following everyone, he had his hands in his pockets, still thinking about the fight he was in and how he'd needed to gain more control over his animal DNA. Having the Black Mamba in him, did it mean that he has a lethal poisonous bite? other abilities like that of a snake? what else can these others here do? whatever it was, he will not back down from from a fight. 

but before the satisfaction of combat and bloodshed, Oliver walked in the cafeteria looking around.