I'm not even approaching it as a nurse. I guess I got lucky working on a fire department after my medic but I would never work for 15 bucks an hour as a medic. We pay our ED EMTs more than that.
Your time is worth what you will sell it for. If you view it as a paid way to do adventure type things then go for it, but I don't really see the value beyond that. Certainly the labor market is a balance of supply versus demand, but if the supply agrees to an unlivable wage it then the free market will never increase salary. I won't even walk into the hospital for overtime if I'm not either getting call in pay or bonus pay on top of the OT.
As a real question how much is it even really worth as a resume builder? You're going to have a doc at any of the high risk events, and the vast majority of what your are going to treat are clinic or maybe urgent care type complaints. With the exception of the actual contestants most of the patient population will be pretty young and healthy. The conditions are pretty cush too; it's not like working in a unstable area of the middle east, the Antarctic clinic, or something like that. Your going three plus months without a code, without a stemi, without a septic shock patient, or anything else resembling real acuity.