A Question Concerning the Passport Checkpoint Scene

Forgive me if this has already been asked and answered but I checked all the messages on this board and didn't see it posted. Also I had just watched this on TV only a few minutes ago so I may have missed a key scene that explained it.

Anyway, the last thing I remember seeing before the scene is them passing the blockade with the elderly couple and driving out of Pittsburgh. Then the elderly couple is getting into a cab and they say their "thanks" and go their separate ways.

The next thing I remember seeing is them getting their boarding passes at the counter and then heading to the passport checkpoint. As they approach the checkpoint, there is a sign that reads "You Are Now LEAVING Canada" or words to that effect. The officer is wearing a uniform for Canadian Customs.

So my questions are:

(a) How did they get into Canada from Pennsylvania (provided they actually did go into Canada in the first place or this is a goof or I missed a key scene that explains it) since Pennsylvania shares no border with Canada? Did they catch a ferry from Erie and cross Lake Erie to get to Canada?

(b) If they did in fact go into Canada why LEAVE Canada to go to another airport in order to take a flight to Venezuela? Why not just stay in Canada since you're already out of the United States? Or just fly to Venezuela from Canada?

Now I did read in the goofs section that Canada does not have any exit controls as portrayed in the movie and it was addressing this specific scene. However it doesn't explain how they got into Canada.