Silly ending (***Spoilers***)

So, the elaborate plan was that Parker will appear with his gun (unbeknownst to him that it's with non-functional bullets) and then may be hold them while Cecilia will go up looking for the money!

What if Parker had tried to shoot them? He would have known then and there that the bullets are fake!

What if Cecilia & Parker, after setting Jigsaw and the little boy on trap, didn't go up and waited for either of them to die and then go and find the money!!

The whole plan was so stupid. They just went lucky that Parker & Cecilia went up the office to find the money while the trap game was still on!!!

Infact, after seeing such horror of her accomplice's death; Cecilia should have stayed and enjoyed the death game, have Jigsaw die, kill Amanda and then go up to look for money.

Silly indeed.