Blood atonement is a complete red herring regarding the JA case.
Like any intelligent murderer JA wanted to dispatch TA with finality.
Many people(myself included) reason that if murder is the aim why not use the most efficient means to achieve this end. Shooting TA in the head while he was confined in a shower stall is a priori the best possible method.
Using a knife to effectuate the murder of TA is uncertain and inherently unsafe.
It stands to reason that JA could have shot TA in the head to incapacitate him and then proceeded to attack with a knife. TA obviously defended himself with a certain but otherwise unknown amount of vigor. JA could NOT have known how an initial knife attack on TA would have turned out. In the knife first theory TA could have just as easily disarmed and overpowered JA since he was bigger stronger and more agile than JA.
It also stands to reason that JA did NOT anticipate a blood bath or the need to slice TA throat.
There is NO reason to believe that JA had a blood lust. TA delivered some 4-5 liters of his own warm blood onto the bathroom and bedroom floor plus whatever amount got washed down in the shower stall. This situation presented itself truly as a HOT MESS.
It is somewhat of a mystery why JA chose to clean up the scene. She certainly had no desire to hide the nature of death. The only reason why she would clean is to expunge any evidence of her presence at the crime scene namely fingerprints, hair fibers, any lingering DNA residue, and her own blood splatter.
[If I had been JA and was bent on murdering TA with a knife alone I would have used GLOVES].
The motivation behind the RAGE and or PANIC knife thrashes is purely speculation. She certainly could have enjoyed the knife thrusts as a source of revenge. But this enjoyment is pure luxury when one is in the heat of battle where one or the other is likely to die in the outcome.
I subscribe though to the panic reaction theory, I think JA shot him first and he did NOT die immediately, I suspect she shot again and true to the Ninja Story the gun jammed. She panicked . She had access to her knife and she began flailing indiscriminately at JA front side and then his back side. Because TA simply would NOT die on the spot JA opted for the coup de grace by attempting decapitation. This scenario comports nicely with the crime scene blood splatter pattern on the bathroom tile and sink.