EDF 5 DLC 1-11 Underground 1 Ranger Inferno Weapons Farming ( Earth Defense Force )

The Ranger can do this reasonably easily but you do need specific gear to achieve it.
Unfortunately, only Flame Geyser F is good enough to deal with the large number of powerful enemies. For the second weapon either MA9 or MA10 will work, you'll need something powerful that has a fast reload for close combat, just in case something slips by the flames. A shotgun can work but it's more unreliable. Complement with Probe Type 5 to help with crates pick up. Only the AR and Fencer can do this mission easily with lower specs weapons.
Have fun,