Travelling while applying inland is not recommended. If she is already on a work visa or study permit in Canada, she would be allowed to come and go but if she is on a visit visa, she is not supposed to be living in Canada as a visitor so an immigration officer could at any time decide that they will not let her enter any more as she has overstayed her welcome. The rule of thumb for visitors is 6 months a year or less.
If she gets stuck outside Canada, she will lose her inland application as she is no longer living in Canada which is a requirement of inland.
