The packpack at the end. (spoilers)

it doesn't hurt to have the money there especially if you think that you'll get it back anyway. This way, if he actually does get his hands on the backpack and look inside, he won't go on a bloody rampage and kill everyone when he sees there's no money. He'll probably just try and leave and no unnecessary deaths. It's not a bad business decision.

My thoughts exactly! If Mrs. Bronson is just gonna send a hit squad after Porter, WHY bother bringing the money at all to begin with? Why put $140,000 out in the open for pretty much anyone to stumble upon if you're planning on killing Porter anyway? This makes zero sense, and as a screenwriter myself, I'd never write in such a sloppy plot hole just so Porter can ride off with the money. If Porter is killed, there's no reason to have the money there. If he survives, why bother giving him the money? If Porter survives, it's only by way of killing a slew of hitters in a public place. Thus, Porter would be on the run from the entire police force for mass murder and endangering innocent lives, and wouldn't have the luxury of hunting down his money any further. He'd be preoccupied with running from the law. Mrs. Bronson's intention is for Porter NOT to get the money at all. Her intention is for him to die without ever laying a finger on the cash. So, why bring it along, anyway? Ever hear of a decoy? A fake-out? It's sloppy screenwriting, period.

At least in the theatrical version the money is used as a bargaining chip for Porter to reveal where Mr. Bronson's son was being held. There's a real purpose for it being present. Plus, they lock Porter in the trunk of the car, and could not possibly anticipate him ripping through the upholstery of the back seat to escape and blow them to pieces via a bomb they didn't know anything about. It's much more clever, much more solid screenwriting there than here.

-NJM