You're potentially always in danger of self incrimination in a case like this. This is when we might sometimes offer immunity, of which there are varying types: (won't use your statements against you, or we won't prosecute you for X crime). Under those circs, I can't use someone's statements against them, unless they are dishonest. There's a bunch of backdoors and workarounds, and it's an annoying process.
Especially in severed gang member cases (trying people one at a time vs. as co-defendants), where even though a dude is a defendant, he isn't a defendant in a case against another person. So there, I'd call him, he pleads the 5th, we take a big break, I get all the paperwork for immunity, judge grants it, other gang member still tells me to fuck off, I ask judge to order him to answer, he still doesn't, and then I introduce a statement of witness through a hearsay exception once all that shit unfolds.
Regarding the initial post, it's flagged as NSFW and I'm at W. Can someone give me a cliffs of the events per the video?
Basic rules are most crimes of violence, I need to prove the defendant didn't act in self defense. Self defense can't be provoked/contrived, and you can't use more force than reasonably necessary. Self defense fades when combat/threat fades. There's self defense of others (that guy's getting killed!), mistaken self defense (I thought he had a gun!), mistaken self defense of others, defense of property, dogs, etc. etc. etc. etc.
Long story long, DISproving self defense is pretty damn tough. Of the cases I've lost, it's getting hung up on this issue. Some states allow for SD as a mere defense, but here I have to disprove it altogether. So if you have even a skimpy claim of it, you can hammer that home and rest on the state not disproving self defense. This is also why prosecuting cops is so challenging. Self Defense is a tough little bitch.