Martin is a former Black Panther who works for a white South African who calls him "boy" during the height of Apartheid and ends up betraying his boss. Should have seen that coming.
When Harry reveals what Stevo did, Martin says tells Harry that killing Stevo would make him a "hero." Vernon immediately chastises him for "making it worse," and Ord asks, "Why would you say that?" It's later revealed that Martin was behind the ambush, so he had good reason to want the deal to go south.
