I'm planning a bit of a disjointed itinerary which involves a turnaround on the UAL service into and out of YXE (from ORD). Is there any reason why I shouldn't be able to land on the inbound flight and then depart again on the same aircraft back to ORD ~45 minutes later?

Will I actually need to clear Canada customs or can I stay airside in the gate area without legally entering Canada?

Or, conversely, is the processing around lunchtime quick enough that this won't be an issue?

Kind regards,
twj