This is a tip not a cheat... sorry

Needed:

1. The “Projectiles” event unlocked
2. Infected vision

Go to the location of the Projectiles event (mark it on you map).

Start the event but instead of doing it just switch to homing missiles and kick on your infected vision and use the helicopter to blow up the surrounding water towers, they will glow making them easy to find.

You get unlimited missiles and get 10,000 EP for ever tower and can average about 200,000 per run.

Once the event ends just restart it by hitting X and make another run.