There was nothing in your decision making that makes you a prat
You heard something unusual & acted on it correctly,
I am in the early stage of my training & it is easy to forget lots of things, but to remember & act on the important things is all that is necessary.
I would commend your instructor for getting you into that state of mind rather than the "it's probably ok" mode. Our overshoot / EFAT area up here is a flooded quarry, if I had a warning while still on the runway I would certainly feel a prat if I found myself scrambling up them rocks, if I were able to!
Well done Captain.