How about a twist?

[Louis]

No: HPFGUIDX 159795

Harry does get DD's pensieve and sees the argument between Snape
and Dumbledore at the edge of the woods and Snape is vindicated. The
argument was about how Snape being on the inside was more important than Dumbledore living. Say Snape didn't want to carry out the deal and die via the unbreakable vow. In that case does Harry hunt down Snape and come clean he now knows all and gets his help? Wouldn't that be a
twist?

Louis