A recruiter can guarantee NOTHING! I was guaranteed so much, and I have been so disappointed over the years. I know many people that have their CCRN and have not been admitted to the ICU. Sorry to be the bearer of bad news. Also if you're looking to continue to take care of level 1 trauma patients then the Navy is probabaly not the best place. Most of the pt's we see are retirees/dependent family members. Rarely, if not ever, do we ever get a real trauma.
Think about it this way, when there is a trauma in the U.S. where does it happen? Not typically on a military base. It's out in town somewhere. Then who gets called, 911. 911 responds as usual and EMS/Paramedics respond and take you to the local level 1 trauma center, not the Navy base. If your looking for adrenaline packed trauma and excitement then you won't find it in the Navy. You may find it eventually IF you deploy, but thats the only time. Sorry but this is really how it is 99% of the time.
Also, regarding the big 3. They can suck the life out of you with all the politics and BS. Many of my friends have been much happier at other midsized commands. And yes, you can request such places. Just don't put a big 3 on your list otherwise that's what you'll get.