The 14-30 is a 30a @ 240v connection. Your 5-30 is only 110v. I'm not sure what will happen if you try to fool the UMC into thinking it's 240v, but I suspect it's not a good thing. Best case it would pull 30a @ 110 which would be ok, and probably get you up to 10mph. Worst case the UMC will bail entirely saying your connection voltage is too low a voltage (only one hot leg in a 5-30) because it's expecting two hot legs (240v) through the 14-30.
If you're in an apartment or condo, you've got a problem faced by many. Maybe EVSE adapters will make an adapter that will allow the UMC to pull 30a @ 110v. Otherwise, you bought an expensive car, spend a $500 and get a 240v connection of at least 30a (i.e., 14-30) which will give you about 22mph.