Factual error: In the scene when they are leaving the Pittsburgh Zoo, the sign indicates to turn right for Interstate 79. However Intestate 79 is about 15 miles to the west of the zoo. Also, it is suggested that Interstate 79 is the turnpike (a tolled road), when actually Interstate 76 is the turnpike and Interstate 79 is not tolled.
Factual error: When Lara's test results show her diabetes is dangerously out of control, she would not have been rushed to the hospital without first running a very quick and simple blood sugar test. Diabetics routinely test themselves several times per day, so the prison medical office would already have the test equipment on hand.
Factual error: Just like in the United States, there is no exit passport control in Canada. That is, when one leaves the country one's passport is not checked by Border Services.
Answer: John's plan to help Laura escape would not have worked, because he would not have been able to plan ahead like he does in the movie. He would to know where Laura would be transported, and when and if she would be transported there. He would not have know any of that as the information is kept secret from the prisoners, and the public.
Even if he did find out Lara was in hospital, Lara would have been transferred to another hospital.
The movie attempts to cover this up by having him send fake diabetic results to the jail. This would not work because jails and prisons do not accept diabetic results from outside labs.