Don't worry about the IV. It's the least important part of the class.
The most important thing you can take away from the combat lifesaver course is to remember 90% of preventable combat deaths are due to exsanguination from extremity wounds or tension pneumothorax. IVs aren't lifesavers. They're cool and exciting, and invariably the one thing that students in these classes get most worked up over. They want to learn the skill so they can save someone's life with it.
The key to survival is quickly stopping the bleeding, assessing for tension pneumothorax, and CASEVAC'ing the patient. Everything else is secondary (except getting the out of the line of fire and/or killing the other guys, of course.)
The utility of IVs placed in the field is very limited. Moreover, indiscriminate use of IV fluids for patients with uncontrolled bleeding may well increase mortality. The current tactical combat casualty care guidelines regarding IV fluids can be summed up pretty simply:
bleeding controlled, no shock - no IV fluids
bleeding controlled, shock - 500-1000 cc Hespan
bleeding uncontrolled (intra-abdominal or thoracic), no mental status changes - no IV fluids
bleeding uncontrolled (intra-abdominal or thoracic), with mental status changes - start with 500 cc Hespan, continue with fluids until MS improves
It's important to remember that IV fluids are usually not needed and may be harmful. Don't let the coolness factor of jabbing a needle into someone divert your attention from the two things that really do make a difference: stopping bleeding, and calling in the 9-line.