I like that junaid is shown to be sort of a rebel among exterminators in many different ways. I can already tell this is about to turn into a rant because of how much I think about him and how many examples just immediately came to mind so brace yourself
first of all. the whole "kill every parasite on sight, no matter how conscious they seem" rule? disregarded. He WAS obeying it- he had been about to kill Hirudo- but once he showed his abilities and caught Junaid's personal interest, he forgot all about that rule, and now he's spending a strange amount of time and even forming a bond with parasite that he was supposed to kill. oddity
second, he's the type to work alone. not exactly rebellious in a way that he's directly breaking any rules, but it raises eyebrows, you know what I mean? he doesn't even seem to really speak to or enjoy being around his coworkers much, except for the gas mask guy, who he's shown to be close with (but because of their similar personalities and tastes in the weirder things, it's safe to assume that the gas mask guy is ALSO some sort of rebel/outcast). I also think that him working alone is an excuse to give him more freedom. He can essentially just do whatever he'd like on his missions. Its how he got away with recruiting Hirudo, after all. I'm sure that if he had another exterminator tagging along, then they wouldn't have allowed that to happen
his little unconventional scissor weapon (among all the other surgical tools in his arsenal), and the way that he doesn't wear the uniforms that the rest of the exterminators do. he stands out immediately.
Most exterminators are either shown or assumed to have a distaste for parasites as a whole, but Junaid seems like the type to lean more towards them than regular people. He is rumored to "like leeches more than people," after all.
the hand that feeds by nine inch nails being in his official playlist
the "I'm a good, clean person!" artwork could be percieved as him mocking the exterminator organization, though that wasn't my initial interpretation of it
dirt by zoe ko being in his official playlist. he's the type of exterminator who only became an exterminator because he wanted to see all the filth up close (and also maybe for cash), not because he supported the organizations ideals. to me, at least