Need some feedback on the candid shot i took

Few months ago i took this photo on my trip of a security guy. the picture was taken from the bus and somehow the guy suddenly stared at my camera right when i pressed the shutter which makes for this really emotional looking picture. personally i'm satisfied enough with the picture, but well i never really focus on portrait so i don't really know if this is a 'good picture' to other people. please give me feedback and some critique on this picture. by the way, feel free to rate this picture on my portofolio, or even the other pictures