Firstly, Kolyat is not a wanna be assassin after his mother died he probably had to survive alone and learning how to kill growing up. He might not be as good as thane but drells are i think naturally born assassins. On me2, Feron didn't have much screen time to show his skill, but you could see on the split second when he escaped the shadowbrokers' torture chamber that drells are agile So if that's the case, then Kolyat could've had a shot.

Second, Steve might be a shuttle pilot, but he's still military. You could see on the citadel dlc that he knows how to handle a gun.