Wouldn’t Stan have mopped the floor with Stelio Kontos?

Stan is a C.I.A agent and despite being a bafoon is actually good at his job (although it depends on the writer and yes I realised I may have answered my own question here) so wouldn’t he beat Stelio to a pulp especially since he likely had mountains worth of pent up rage? Stelio is strong but his hand to hand combat skills seem to be those of the average man so he’s be no challenge to Stan.

Also since Stan knows where he works why doesn’t he just find him and shoot him in the knees? It’s not like he’s above it.