Please do not attempt it.

I would suggest buying a ticket. There are no guarantees when non-reving.
Besides if you start early you might find a great deal online.

When you say, "I need to get there in time" That means buy a ticket. Seriously, it is not worth the risk.

I sent my son to study abroad in Cairo last year. I never once considered him to non-rev there, and he was even going in January when it was probably a good time to non-rev. It just wasn't worth the risk of not getting there ontime.