If you're going to have two characters that spend a large portion of the movie yelling at each other emotionally, maybe it's best to NOT cast a Brit and a Aussie, neither of whom are all that adept at an American accent.
And bonus, what we DIDN'T learn: so this has troubled me for some time, but so okay, if Jigsaw's whole game is that he makes people fight for their survival, then what of the dude with the opiate overdose who had no point but to lay there and have Shawnee sort through his organs? How was he supposed to save himself? Oh Jigsaw, you with your ambiguous morals and chic boxer shorts.