How dangerous are Yellowjacket wasps

I just got home from my school to find that my main enterance to the house (my garage) wouldn't open due to a dead battery in the garage door keypad. There is another way in, however, it's 2 inches away (literally) from an active Yellowjacket nest which is resting in an empty light socket. There are about 2 still in the socket looking around, and there's one flying near the light socket. My question is, if I risk fiddling around with the door to try to unlock it, is there a good chance that I'll get swarmed and/or stung? I'm sphecksophobic by the way...

Also, when you spray a nest with wasp poison, does that mean that the wasp nest can never be a suitable living space for future wasps? I sprayed this nest a couple of years ago and hadn't had any wasp problems until now.

That's like asking how dangerous is a peanut, well how allergic are you to wasp venom? If you are deadly one sting will kill you, if not at all a bunch of stings causes just swelling. You are overreacting, if you pass by it to open the door they may get interested but they won't swarm you, just don't upset it too much if you must pass it, and by that, don't poke it with a stick, and for how long the poisen lasts you just answered your own question.