You were a very apt pupil

Ferguson's rage is at his own comparative failure: The object of desire was more skilled and more willing with her earlier partner. He doesn't seek revenge on Gavin Elster, because such a revenge would not circle back on Ferguson himself. Instead he attacks the desired one, seeking to restore the emptiness he lost.

Elster is the successful Pygmalion; Ferguson is closer to Icarus. And even closer to an unsuccessful and rebellious puppet who's got no strings to hold him up.