The 'sound' that is heard on night #5 before Katie wakes up

No, and I believe the moment the door slams is further into the movie and the moment Toby screams is when Micah wanted him to bring more action and it just so happens that night, he did, but I agree, that was the moment I first got into the movie, not for the faint of heart, and I presume it was out of fury because it was very sudden and soul shattering, giving them a taste of how evil he can be, and what's even more creepy about it is that after Micah and Katie go downstairs to investigate and then come back up, you can hear slight thuds in the hallway, which slowly stop through the night, as if this particular 'scare' was not of the norm and maybe he wasn't happy with Micah taunting him.

But I was actually referring to the first nights when Katie has a nightmare, there is a very quiet audio in the background that occurs before she wakes up, remember the audio that Micah caught which he showed Katie and Katie's friend the next day who were having 'intense' girl time playing with beads? well, if you listen carefully, you can hear that exact audio just before Katie wakes up, it's very incoherent and sounds in-human, like a deep whisper, I keep trying to make sense of the vocals, but it's all over the place, but it's weird how Toby actually 'spoke' to Katie while she's sleeping, maybe that's why she had the nightmare? it's actually a classic symptom of Demonic hauntings where victims suffer nightmares induced by the Demon, and the day where Micah shows Katie how she sleep walked out of the bedroom and wasn't acting herself, she mentions something about how she was having these 'nightmares' and wouldn't elaborate further other than they were 'gruesome' in nature, creepy.