I wouldn't worry about the medicine degrading. I've accidentally left vials out of the refrigerator overnight and noticed no difference in performance the next time I injected. The protector case you listed seems nice:
http://www.everythingmedical.net/Durabl ... uctid=2895You shouldn't have to worry about the plunger being accidentally depressed. If you like that case well enough, buy it and haul it around for a week. Just draw some water into a needle and see how it performs. I can't imagine that you'd lose any fluid at all.
You can also use the Frio wallet that you can store in a pocket. The Frio can keep insulin cold for 48 hours. I used it for a trip from Florida and California and back with no problems. The smallest Frio has space for a vial of Trimix and a couple needles. With the Frio you would have to load the needle before you inject. Take a look at it:
http://www.amazon.com/FRIO-Duo-Insulin- ... words=frioThe bottom line is as another poster suggested: Try not to worry so much about these things. It doesn't matter if you have a prefilled syringe or you need to load from a vial. Either way the process is only going to take 2-3 minutes during a bathroom break once you are comfortable with how to inject.
You'll probably find that the biggest challenge is overcoming your nervousness to inject while on the date. You'll have a lot easier time if you just tell your date that you take an ED drug in liquid form that works a lot like viagra, but you have to inject it right under the skin -- and you'll be right back!
A buddy of mine did that on a date once and the woman then pulled out her own Frio wallet showing her insulin for diabetes. They both had a big laugh out of it and proceeded to make love for two hours after he injected in front of her.
One more thing: An old eyeglasses case that you can pick up for a couple dollars is an option as well.