The Last Moments

Jan Roseboro's last moments were spent fighting for her life.
She took her last breaths in her own swimming pool.
We know from the autopsy that she was alive when she inhaled the pool water.
The L-shaped wound on her head has been a focal point for many of us.
We don't know that much about it but it has made us all assume there would have been alot of bleeding. Especially from a head wound.
If she ended up in the pool seconds after being struck there would be no blood to find outside the pool. Was the head injury sufficient to knock her out or simply stun her?
How did she end up in the pool and was she alert enough to be fighting once she was in there?
I am wondering if we've been hung up on a clean up that wasn't really necessary.
I think this killing took far less time to commit and even less to clean up than we thought.
The call was made right after 11 pm to 911. Mike only picked up that phone when he knew she was dead.
He knew it at 11pm or a few minutes after that.
He needed time to pull her out of the pool and position her as if he had been doing CPR. That was just a few minutes.
This may have been much simpler than anyone realizes. The "tool" may be something quite simple too.
He snapped, the attack began and it got way out of control. In a rage he beat her, strangled her and threw her in the pool or they both ended up in there.
She died essentially due to drowning. How did she drown? Did he actively hold her under the water or did he just let her go once she was in the pool unconscious?
This all may have taken much less time than anyone realizes.