lgreenberg, I have my iPhone in an Otterbox defender, and I could not be happier with the protection it offers my iPhone. However, I have discarded the belt clip/holder after losing my phone in the dark answering a domestic disturbance call. I know you are a firefighter, and you likely have access to a store or supplier that offers 5.11 gear. 5.11's "C5 PDA/Device Carrier" uses molle attachments to clip to a belt or other piece of gear, and there is a positive nylon lock which holds the phone SECURELY. The silicone skin of the OB defender also makes a friction lock inside the carrier once you get it strapped in. It WILL NOT come out of this case unless you tug it out....
Just a heads up....
Tried to post a link to the 5.11 C5 case, my post count won't allow it