Goofs

In one scene as Emma was dragging Mark towards the stairs, blood is clearly visible on the bottom of Mark's feet. (When did he get the chance to walk through his own blood?) In later scenes the blood vanishes from his feet.

After the ice cracks under Bobby, Emma and Mark, they fall into the lake. When Emma needs to get out of the lake, the ice is no longer cracked and she has to make a new hole to get out.

It's not that the hole no longer exists, when you go under icy water, one often loses sight where the opening is. She can be seen searching for the opening, but cannot find it, and is forced to create a new one.

After Bobby is stabbed on the ice his unchained hand is a couple of feet away from Emma, when the ice cracks and Mark falls into the lake the effect pulls him even further from Emma yet he is able to grab her by the throat and drag her in with him.

At the end, Emma's struggle creates a huge hole in the ice which she, Bobby and Mark fall through into the water. After the fight under water, that hole is no longer there and she has to stab the ice to create a new one.

Some viewers claim Mark's body is not handcuffed to Bobby, when Emma drives the SUV into him, but this is incorrect. He is clearly seen being dragged alongside the car, and since it has been established earlier that the handcuffs are connected with a chain of some length, there is no continuity error.

Through the majority of the movie, Emma is wearing her husband's shirt. While it is difficult to tell with tux shirts, since the majority use studs (which can be taken out and reversed) down the front and on the cuffs instead of buttons, she did in fact pull it along the handcuffs to turn it inside out and wear it. It is shown that this is the case because the top (which is the only) button is on the inside when she wears it, and not the outside.

Emma's "shoes" are often seen as being goofs. Although she isn't shown making the first pair, it makes sense that she would remove them after being out in the snow. She flees to the boathouse in a hurry (without shoes). The criminals say she won't get very far without shoes, she makes a new pair.

There is no way she could have put on her husband's shirt when handcuffed..

When Emma is first seen wearing her late husband's shirt, she has his untied bow tie hanging around her neck, until the point when she uses it to pad the handcuffs. She wouldn't have taken the time to add this accessory to her outfit when it was simply to keep her warm.

It had already been stated that the snow/ice used in the outdoor winter scenes was actually paper and foam;nonetheless,no explanation is given as to how Emma (Megan Fox)can walk around in what is supposed to be ice and snow in bare feet with no noticeable effect on her.

While she couldn't remove the handcuff from her arm, she should have been able to break a few hand/wrist bones and remove it from her husband early on.