Those I don't think the doc even needs a fancy cooler, if I understand correctly they need to thaw this first, by the time the individual doc gets it they need to be thawing it and then using it quick. (I don't know what thaw procedures are though)
But I think you're overlooking something rather important: Storing liquid nitrogen in a vacuum flask only keeps the liquid nitrogen cold for hours or days. It doesn't keep the thing cold that you're cooling with liquid nitrogen.
The week you get to use it is after the dose has been created. If it's brought below temperature for any length of time, it can presumably DESTROY the dosages affected by temperature.
See the current flu vaccine storage protocols, for example: https://www.cdc.gov/vaccines/pubs/pinkbook/downloads/vac-sto...
"Regular temperature monitoring is key to proper cold chain management. Store frozen vaccines (Varicella, MMRV, and Zoster) in a freezer between -58°F and +5°F (-50°C and -15°C). Store all other routinely recommended vaccines in a refrigerator between 35°F and 46°F (2°C and 8°C). The desired average refrigerator vaccine storage temperature is 40°F (5°C). Exposure to temperatures outside these ranges may result in reduced vaccine potency and increased risk of vaccine-preventable diseases."
Any you get a week after thawing it to use is anyway, so you don't need the cold storage where the end user is. I don't know what the thawing protocols are of course.