The Rav-ages of Caustic-X Walkthrough

Start the Quest: After defeating Alesis Hernandez in Monarch Studios, exit the boss arena and head through the back door. Listen for a distressed call on a nearby radio. Interact with the radio to speak with Hanna, who will ask you to help her med student friend, Rav, at Halperin Hotel.

Find Rav: Travel from Monarch Studios to Halperin Hotel. If you haven't unlocked fast travel, the route is through Beverly Hills, then Bel-Air, and finally to the hotel entrance. Upon arrival, an explosion will occur, blocking entry with flames. Defeat the Crusher zombie and burning zombies that emerge. Once the flames dissipate, proceed to the ballroom where you defeated Becki the Bride. Rav will be on a balcony.

Find the Ambulance: Speak with Rav, who explains his interest in the Caustic-X goo. Exit the hotel's main entrance and follow the road to the far corner of the parking lot to find an ambulance. Be cautious of the 'Ambulance Driver' caustic zombie, whose attacks are similar to Alesis Hernandez. Also, deal with regular zombies and a Crusher. Ignite fire behind a toppled bus to help burn zombies, especially the Crusher.

Collect Caustic-X Shipment Receipt: After clearing the zombies near the ambulance, use the water in the back of the truck to clear the Caustic-X goo on the ground to your right. Collect the 'Caustic-X Shipment Receipt' from a biohazard box. Return to the ballroom.

Defeat Zombies in the Ballroom: Back in the ballroom, prepare for a large zombie horde. Stock up on med kits and note the locations of food and batteries for electrocution. Turn on the music to trigger the onslaught. Utilize the environment, such as batteries and water, for crowd control. Beware of grenadier zombies; use them to your advantage by luring other zombies near them before they explode.

Kill Zombies at the Swimming Pool: After clearing the ballroom, Rav will ask you to go to the hotel swimming pool to experiment with Caustic-X. Head out the door to the right of the foyer, down the steps to the right, and to the pool area. Kill 14 zombies. A simple method is to herd zombies to one side of the pool, then run to the opposite side. They will walk into the pool and burn in the acid. Alternatively, kick them in or fight them directly.

Complete the Quest: After killing 14 zombies, return to the ballroom balcony to speak with Rav. This will complete the quest.