The human heart pumps about 5 liters per minute. The human body only contains about 5 liters of blood.
The arteries in her right arm were severed. According to OP's timeline, she would have bled out long before he carried her down the steps 10 minutes after shooting her.
There would be no arterial blood splatter anywhere except the toilet stall.
He bashed the door first - screams- shot her - pulled out the pieces of the door - made calls - carried her down the steps
I put it to you, <modsnip>, to explain how the arterial blood splatter got on the walls and the couch downstairs if Reeva had been shot through the arm 10 minutes earlier. Why were there no large pools of blood in the bathroom? OP's timeline is physically impossible.
I also would love to know why Oscar needed to have his selective amnesia for the first portion of his trip to the stairs. He says he doesn't remember carrying her from the bathroom to the middle landing, not the top, of the stairs.
You know why he can't remember... Because there is arterial spurt only in that section of the walk and there's a REASON he doesn't want us to know something
He remembers perfectly well exactly how he pulled her out of the bathroom, her head rested on his shoulder, he couldn't lift her, he placed her gently on the bathroom towel/carpet, he asked Stander for help...
BUT... He doesn't remember:
1. The first half of his call to Netcare, what HE told them but he specifically remembers what THEY said to him.
2. Telling Baba "Everything is fine"
3. The first half of his walk with her in his arms, to the middle landing of the stairs
4. Getting plastic bags, rope and/or tape
No, that's not slightly suspicious whatsoever!
Anybody who genuinely thinks he was helping her and wasn't trying to cover something up and/or wait for her to die is simply ignoring HIS evidence and in denial.
I loved LindaNJ7's comment about take Oscar out of the equation and insert some other random person and would we even be pondering this right now (paraphrasing). I think not.