This is likely the first neutral area that you visit. In these areas, violence is prohibited. If you shoot your weapon, an alarm will sound you will be attacked by the security force. If you walk up to the first stationary soldier in white and press , he will explain that attacking in neutral zones is forbidden. It's a good idea to keep your finger off , and keep it on for when you need to use the grappling hook.
Start walking to the right. An enemy soldier in run will run toward you with a knife in his hand. He will threaten you, but do you no harm. Beyond him, a man standing before door A will answer your inquiry and explain that he doesn't know anything about a "Super Joe." Stepping inside the the door, you will find a room with a single bullet in it. Collect it before it disappears, and then return to the outside.
Grapple up to the platform above and continue right. You'll have to drop down, stand beneath the soldier in green, and grapple up to the ledge. When you pull yourself up, the soldier standing there will tell you that you can find flare bombs inside the next room. Step through door B, and you'll see the flare bombs sitting in the corner. You don't have to worry about the spikes, you can use your grappling hook to reach across and collect the flares.
There's nothing else to do here, so you can leave either through the right or back to the left. At this time, you're ready to enter Area 4 with your newly acquired flare bombs. However, since you have no continues yet, it may be worth your time to intentionally intercept some of the trucks on the map in order to earn continues. See the Walkthrough page for more information about these encounters.