As mentioned by others earlier, they will simply tell that they cant send you sooner by default by most officers. Many people requested and very few received it soon. Requesting urgent certificate is not automatic exclusion from the oath.
Every oath related email needs to be attended. And who knows if same person will attend and respond/take action or different officer will attend different emails of yours and act differently(one will try to expedite and other may not) which may delay issuing certificates as there are multiple requests from same candidate. Is this outcome 100% certain? No one knows.
You can find out by sending email if you are ok for any delay. I would mostly think that they will just ignore the emails other than the oath form but who knows.
You should simply leave and ask your friend to send it via fedex/ups. Only for passports, many countries have restriction to send out but this is only certificate hence cant be easily sent/received in/out of any country. YOu dont need to wait for it. Many including me and my family didnt wait inside Canada till certificate is delivered.
If you dont want to get lost in postal then you have to stay few more days just like you were waiting for oath. Not much choices.