Reznik has a lot of experience in ship engineering – he’s been working on ship engines his whole life. He doesn’t have Cooper’s natural gift for engineering, but worked his way up to his position through sheer hard graft.
He likes the perks of being an officer, such as the responsibility and the authority over his own domain, but also enjoys the relaxation he gets from working on the engines. He likes to be the boss, and he likes to work with his hands. However, these aren’t distinctions he would make himself – he does not analyze, he just does.
Whether on the bridge or at the core, he’s argumentative and resistant to other people’s ideas. On the bridge he’s usually forced to bite his tongue, but in engineering he never has to.
He works long hours and works his crew as hard as himself. He doesn’t take care of himself however, and most of the time finds himself running on empty.