I understand the reluctance to trust BSL's version.
I'm going to say that I believe most of it though.
Regarding the gunshot, if she stabbed him right away on St. Landry, and then he stabbed her, then I don't know why, if she was already dead, or so he thought, he would drive out into to the cane field to shoot her in revenge, then leave with her body. He went to the cane field with some purpose in mind. But then he didn't leave her there. If he would be worried about a bullet being traced to his gun, he wouldn't have wasted time going there if he shot her during the initial bump and grab - he would have headed home to tend his wounds and regroup, with her still in the truck. And I don't think he shot her on St. Landry during the initial altercation. There are enough houses close enough, including frat row, and you know some Greeks were still awake at 2 a.m on Saturday morning, that someone would probably have heard a gunshot.
I think precipitating point was Mickey calling for help. BSL said he threatened her with a knife. I see no reason to disbelieve him, because it doesn't help him to lie about this particular thing. I would then think that she Maced him very soon after that. If she called 911 on the street, then she maced him and grabbed the knife and stabbed him right there on St. Landry, then he stabbed her and threw her in the truck. If he was stabbing her outside the truck, though, I do think she would have screamed, and there would have been blood evidence on the asphalt. Someone possibly would have heard her from one of the houses, as they are not as far away as it seems. Instead, I feel she tried to call for help once he headed north out of the area, instead of taking her to the hospital or taking her home. She may have even given him her home address and thought he was taking her there.
Yes, her mom said she wouldn't have gotten in the truck. but that's not 100%, IMO. He likely tried to act like he bumped her on accident... then once it was seen that the bike wouldn't roll, the logical question is, "where are you headed?" She says, "home." He says "where," She says near Congress and Ambassador. He says he'll take her home. It's late - she feels sick - she doesn't want to wait on the street all alone waiting for friend or family to come get here - and he acts very charming - and does get her in the truck without a fight. It's when she realizes that he's not taking her home that it hits the fan.
Given BSL's multiple wounds, I said it awhile back, and will repeat, that the varied locations tell me that they were in close quarters, where he didn't have the maneuvering space to avoid her attacks. This really does sound like inside the truck. She would have had several slashes at him as he squirmed behind the wheel to avoid the blade while being Maced and trying not to crash.
At that point, IMO, rape is no longer on the table. He hurt bad - there's blood in his truck, his plan's blown, she's badly or mortally wounded, and so now it's no longer about sex; he's in a life-or-death MESS. I'm not going to opine that sex was on his mind anymore, from a badly stabbed victim.
When he went to check for a pulse, he may have had his own pulse pounding so bad, he couldn't feel hers - especially if he used his thumb, which has its own pulse. Plus, if she had blood loss, and certainly was in shock, her pulse could have been very weak and thready. AND - if she kept her wits about her - she meditated and went to her happy place and started thinking really hard and slowed her breathing down to almost nothing. If she had spiritual reserves and an iron will, I can see her playing possum and fooling him, in his pain, rage and panic.
So he gets into the cane field - she's still alive, though injured - how bad is anyone's guess - and when he hears him get out of the truck to come around to her door, she opens her eyes, the knife is on the seat, and she makes her last, valiant stand. He opens the door and she "jumps up" off the seat (I think this wording is key). She stabs him - he staggers back totally freaked out because he thought she was dead - he nearly craps his pants from the horror-movie shock -- she comes at him again - he stumbles back - no knife in his own hand - and reaches into his shoulder holster or the small of his back for his gun and fires because she's about to stab him again.
Due to the sound of the gunshot, now he's afraid someone will have heard and maybe a cop will swing by and investigate - so now he can't leave the body because they will be hot on his heels if they find it.....
So he throws her back in the truck and hauls butt out of there - thinks of where he can go now.... and thinks of Pinseclair cemetery... goes straight there.
Anyway, I'm tired and my mind is mud.
But myself, I believe Brandon told it pretty straight, for one reason especially: I think the cops put the fear of God into him that if he lied about one thing in the confession, they were going to make sure he got the needle.
This all leads me one place:
Mickey fought, and fought, and fought, and never gave up, put a whupping on him, and at the end surprised him so badly that he will never be able to erase the image from his mind.
This is where Mrs. Shunick and I concur: That last image of a seemingly dead Mickey springing up and stabbing him will turn his guts to water for the rest of his life.