I know it has been discussed at length but I just watched the original video that TS posted. I turned it off because I could not bear to listen to the audio anymore but slowed it down and watched clip by clip.
Here is my analysis:
Definitely can see Laina in the beginning. She seems to still be awake, as the lights are on and in the audio it seems TS is addressing her. Since she was awake during, at least, this video, and you can hear TS berating Gannon about what ever happened, we have to assume she has knowledge of the incident or at the very least, what condition he was in at this time.
She then leaves what must have been the master bedroom because when she exits, you see the kitchen directly in front and as she turns you see the tv.
Due to the amount of walking she does, I believe she walks into what is listed as bedroom #2 or the front bathroom. Whatever room it is has the lights off and it appears as if Gannon is laying either on the bed or floor on his side. At first I thought maybe she walked to the garage but I think it is definitely this front area of the house.
This part is traumatic as I realized what I was seeing. Without question to me, it appears that Gannon has injuries to his face. I don't see him being shirtless. In fact, it appears to me that he has a dark-colored shirt on.
I am not one to say I see something when I don't or try to make images out of nothing but as I slowed this down and reviewed clip by clip it was quite easy for me to see him laying on his side with facial/ head injuries.
Has it been confirmed that Gannon's room was in the basement? I'm wondering if in fact the front bedroom was his and that is where they found the "saucer" sized puddle of blood.