Examiners are very understanding and realistic people, and will want to clarify all these problems before you get off the ground, so don't be afraid to ask before you get going.
In this case though, as above, Mayday is only if it's real, and a practice PAN is usually only by prior arrangement, or at least starting with "request a practice PAN" so they can tell you to bugger off if they're busy. Having spoken to the controllers at 121.5 in person, they like the practice as much as we do though, so don't be afraid to ask.
