And this, I think betrays where you are going wrong. Because I do think you're misunderstanding the issues here, Trotterly.
If he intended to fire to "neutralize the threat" then he is guilty of Dolus Directus. He achieved his desired outcome...the person behind the door was "neutralized" just as he intended. Obviously then he needs to convince the court that he was legally justified (PD or PPD) or could not be held legally accountable (Insanity) both of which negate the direct intention.
DE is what you have when the person does NOT intend the outcome. When they do NOT set out to kill anyone, or "neutralize" threats. But, while doing whatever they think they are doing, and for whatever reason they think they are doing it, they continue in the knowledge that someone might get hurt...and someone does.
We must ask....
Did Pistorius not know that shooting into that toilet could hurt whoever was in it?
Whatever he was actually directly intending (if anything) did he continue to pursue his aim reckless to the safety of the person in the toilet?
Did he genuinely believe he had every right to KILL whoever was in the toilet?
And, by the way, on the one hand you're accepting his, "I just wasn't thinking", while on the other you have him "intending" to "neutralize" the threat. Both cannot be true, I'm afraid.