Don your best "I'm a functioning member of society" face, and make sure to pack your essentials: 3 days' worth of non-perishable snacks, 1 liter of water, and a spare set of batteries for your flashlight.
Grab your designated evacuation buddy, and proceed to the designated exit. Remember, it's not just about you; it's about the 17 people in the bunker with whom you'll be sharing a 5x7 foot room for the next 3 months.
Once outside, enjoy the fresh air, and take a moment to appreciate the irony of having to re-enter a world that's now a dystopian wasteland.