The E-POD shield is the APC's "weapon". It is a defensive shield that is activated when the driver of the APC uses the attack button. People inside the shield can shoot out. However, people outside cannot shoot in. Warhawks that touch the shield explode on contact.
NOTE: If an enemy goes inside the shield, and you go out, you will NOT be able to damage the enemy, but the enemy will be able to damage you. MAKE SURE you stay inside the shield!