Why would it be improbable? there can't be that many universities with architecture major in Seoul and he said that one was the best, of course a rich pampered guy would get into the best by connections.
On a different note, I wonder how the MC will carry his revenge (they reunited so fast that it makes sense he isn't over the a**hole yet), having him expelled or something would be the best but it would be hard against a guy with connections...