In the right place at the right time.
The key is... he was willing to act at that right time.
I think Ramsey is someone who is typically uninhibited... you see it in his speech, his mannerisms and in his actions coming to Amanda Berry’s aid... he is not analytical, or a deep in thought kind of person... often it is people who are of the uninhinited type who find themselves the unintended hero... kind of like Forrest Gump... he just did what needed to be done without having to weigh anything first... a more analytical or thinking person might have hesitated... might have condidered, “hey, that’s Ariel’s house... can’t be anything wrong there.”