It's not a case of getting in or out - but having someone on the inside to help control the situation would have been an advantage and it explains how Sheila seemed to remain passive without putting up a fight.
He didn't need anyone to help control the situation, that is why he attacked while they were sleeping. You attack people in bed precisely because that is when they are the easiest targets.
35 Remington is a large caliber with a loud report. He had no moderator. DeFeo shot his parents 4 times. No one got out of bed. He next went to his youngest sister and shot her. She had her eyes open so was awake but didn't appreciate what happened enough to get out of bed and was killed with her head on the pillow still. His brothers were killed next and though her room was right next door they didn't wake up. After these 7 shots the gun was empty. At that point his other sister got up. She didn't know what the noise was that had woken her up she heard the dog barking though. She looked down into the hallway and asked is that you Ron and he said yes go back to sleep. She didn't realize it was gunshots that woke her and went back to bed. This was quite unfortunate because he was able to reload the weapon then go into her room and shoot her in bed too.
You you have to be fully awake and then hear gunshots to appreciate that is what you heard. Most people just go back to sleep and if they hear their dog bark they often will ignore that and go back to sleep and just hope the dog stops. It takes a while before most will actually get up to silence their dog. Unless you live in a bad area in which case you run to make sure no intruders are around. It takes something like that for people to usually pay heed. There are cases where there were fires and yet dogs have had to basically drag their masters out of bed to get them to realize something is wrong.
