WARNING: The following contains spoilers for Boruto: Naruto Next Generations Episode 185, "Tools," now streaming on Crunchyroll.
In the Boruto anime, Kara is spiraling deeper into civil war following Jigen's realization he had traitors in the camp. Members like Victor and Deepa already hated each other before, but now everyone is going at each other's throats following the loss of the Vessel.
On top of this, as Koji Kashin's search for the Vessel keeps hitting roadblocks with Ao, Episode 185 hints there could be a second Vessel: Code.
Jigen needs the Vessel so he can turn it into the ultimate super-soldier. As Code tries to ambush him, the anime is dropping clues that Code could have another purpose. Jigen wants him on a special project, overseeing his war chest, but he indicates Code has much greater importance than other members. The fact Code's a powerful warrior also makes it odd that he won't deploy him. Why doesn't he want to send Code out into the field? The most logical answer is that he wants to protect him.
Delta adds to this theory later on when she and Code argue in the training chambers. He cuts a pillar down and tries to drop it on her as they both call each other out. They each think the other's a traitor, and Delta claims that Code would benefit from the Vessel going missing. He's calm about being called a spy, even laughing it off, but mentioning the Vessel inspires hatred. His reaction is odd -- he's never been seen this angry before.
Given that he has a robotic body engineered by Amado, just like the Vessel, it could be that he's a weaker prototype. Even sp, Jigen could still use him if he's desperate enough, so Delta is apparently picking at Code's ego. Clearly, it's not about Code being good enough to find the Vessel -- it's about him not being good enough to be the Vessel himself.
This may explain why Code tried to blindside Jigen: not to harm him, but to spar like a sibling showing he's ready. Jigen says Code's not up to par, which hurts Code's feeling a bit, but he knows Jigen still has a use for him. Delta's words cut deep, making it clear that Code hates being second fiddle. All of this explains Jigen's tolerance of Code and why he's keeping him in the lair -- he'd only hold something so close to his chest if it were valuable.