Carrying them around might be a different issue. If you're taking them out with the intent to use them on a given patient, you should be fine. If you take them out to carry them around just in case, that might be more problematic. I can't check out controlled drugs in the hospital "just in case". They have to be for a specific patient. It didn't used to be that way, but it's much more controlled nowadays than it used to be. I think you're much more at risk for accidental loss or broken amps/vials/pre-loads by carrying them around, and of course a broken vial is supposed to be documented as a narcotic discrepancy.
Inherent for us is that our narcs aren't pulled for specific patient use, since we have no idea what patients we'll have or what needs they'll have when we roll away from base. The schedule V/IV/IIIs are all prescribed by the medical director to the service, essentially "for office/clinic use", the schedule IIs we pick up with a 222 from our own DEA MLP license.
Further, and if anyone cares I'll find the cite, we're allowed to bypass the two locks rule by carrying them on the person and in the direct control of an authorized administrator...I can't remember off the top of my head whether they have to be sealed or not, I didn't pay much attention since I couldn't imagine not sealing them.
Don't know how it is with EMS, but any time we start accumulating discrepancies in the hospital, regardless of the reason, it will raise eyebrows. I will show the broken vials to the pharmacist and have them document, or, I will tape broken pieces of the vial, with the label, to the narcotic discrepancy form. Too many discrepancies in too short a period of time, and we get to go pee in a bottle with a witness - refuse and you're fired - it's that simple.
Discrepancies are a problem for us as well, the biggest problem with them though is that there's some rather vague language in the DEAs rules. Specifically, the process for a loss requires an internal investigation (always) and a notification of appropriate responsible LEOs (If applicable), and then a notification of the DEA if it qualifies as a "significant loss", but they don't define what a significant loss is.