Plot hole: Julia dies in the underwater escape trick tank because the axe couldn't get her out in time. However, if she was able to open the lid from inside the tank, get up, over, and down, then close the lid (all quickly, silently, and without assistance) when the trick goes properly, then there is no reason that the four men standing around could not have simply lifted the lid, either acting a key in the fake padlock to preserve the trick, or using a key if it's real. At this point she could have gotten her head above water and draped her hands over the side of the tank to stay up. That done, the crisis is over, and she must only wait to calm down enough to get herself down, or be assisted. Cutter built the tank, so he knew how strong the glass was. The only explanation for using the axe was to allow Julia's death, thus advancing the plot.