Nitrox

I have my NITROX card and we evaluated it for public safety. NITROX doesn't make you superman, it doesn't let you go deeper, you may experience a slightly quicker recovery but that is about it.
Prior to you dive the air needs to be tested. (do you really have time for this on scene) once used for NITROX the tank can't (SHOULDN'T) be used for air again because it would have to be preped for NITROX before being used again (expensive) Blending gasses in your own station or on the scene is just goofy so you would have to rely on a dive shop to fill your tanks. Our guys are limited to 20 minutes bottom time anyway so for us their is no advantage and a lot of disadvantage.
I consider my training a little experience into a much larger mixed gas world and a great tool the next time I'm someplace nice.