Very often the proof in the pudding of Oscar not being a fearful guy is the fact that he had the patio doors open. He lived in reality, in the real world, in SA where by all accounts it was a hot muggy night, one can pretty safely assume that others had their windows open also otherwise it is not much of a logical leap to believe that they would not have heard any screams hundreds of yards away. All of these people are wealthy so having problems with air conditioning is possibly a chronic and common problem.
Oscar left this home, he took off his prosthetics, he allowed multiple people in his home, he showered (how vulnerable is that), he didn’t have armed guards, his home was not a fortress, he left his second story patio doors open, none of that means he was not paranoid about his own security. Being paranoid and diligent about his own security does not mean he stood sentry 24/7 with a cocked gun, it simply means he was more diligent and concerned about his safety than most folks would reasonably be, even the folks who shared his gated community.
He was also prone to react to perceived danger immediately and without hesitation. His disability lent itself to that fear and to his “imminent danger” responses.
Something interesting is Oscar’s beloved quote form his mum, (this is not verbatim) “The man who crosses the finish line last does not lose the race. It is the man sitting in the stand who has not joined the race.” Oscar would never fail to respond to a perceived danger. It is not in his nature or his learned behavior. Did he act recklessly even if he thought Reeva was an intruder? In my mind yes.