Vegas knows the family matters, and he knows Kinn. But does he know Porsche? Especially the one who returned from the forest? Korn said Kinn has a new, changed look in his eyes. Porsche is the same. Vegas isn't looking, so he has missed it — he doesn't know Porsche loves Kinn.
“He wants everything that belongs to me. Promise me, you must return to me.” — Porsche trusts Kinn. He is playing Vegas in his own game, saying what he wants to hear, instigating him. Meanwhile, having Kinn and his gun means the most to Porsche now, not whatever Vegas can offer.
Porsche isn't just rebellious, he also thinks a lot, and keeps it close to his heart. This is a man living with the realization that kinn, someone he has fallen in love with, lives with real danger and enemies surrounding him. People want him gone— Porsche can't allow that.
Vegas has a mole in the main family— he knows what goes on there, and has indicated that to kinn a lot. He shows Porsche how different, more warm, casual and happy the second family is, and how he treats his own people, compared to Kinn who is colder and ruthless at first glance.