We're Going to Need Guns
When you're back in the streets, you'll have to go to Friendly Fire. Access your mobile phone and set your GPS to the weapons shop. Like any sandbox game, you're free to roam the city before each missions, find collectables and do optional activities at your own whim. Just head to the shop when you're done messing around.
Once in the store, purchase an upgrade for your pistol and baseball bat if you want. Don't forget to buy some extra ammo as well. Once done, you'll have to head to the armory.
After reaching the armory, work your way inside. If you want to make your job easier, you can hijack a Bear (armored truck) and use its mounted machine gun to take out the guards. Once cleared, go to the marked location and hold your position until Pierce arrives.
You'll have to defend your position as the bomb is loaded. Use the Reaper's unguided and guided missiles to take out the enemy vehicles and later, tanks. Continue doing this then run to Pierce's chopper when clear. For the next phase, you'll have to shoot down military choppers in pursuit. Keep doing this until you reach your hideout. Mission complete.
We're going to need more guns!
Crib – Shaundi's EX's Apartment
Weapon – Reaper Drone
Saints Book Unlocked (Find Assassination Targets, Vehicle Theft Lists and Challenges in your cellphone)
Note: You can basically do some free roaming at this point of the game. You can start taking over territories, buying properties and stores but I have to suggest not to exceed your hourly income over $5000 at this point. Your transfer limit is only $5000 and anything exceeding that won't be credited. After completing a few story missions, your limit will also increase.