Responses
Hi, from what I gathered :
Before, Jake would execute any plan seamlessly without questioning orders. He wouldn't have selected which files to give : everything would've ended in his boss' pocket.
But now, he has a new purpose. He loves and desires to protect Shin. Therefore, he selected which Merciful files he'll divulge, keeping some for himself to use as collateral if anyone tries to betray or attack them.
Basically, his priority isn't the perfect execution that fit his personality because he has changed emotionally : he now cares about Shin and he wants to make sure he is safe.
No idea if this interpretation was clear, do tell me ! ^^
I don’t get the part about the mercifuls’ files