First, place your character on a safe place (I put him behind the forklift) and then, wait. Really, just wait. Go away from your keyboard, or, at least, let the game play by itself. About one hour later, you should have, at least, 42 people who died by walking on the acid path. This is very interesting because it means less people to see the dead bodies, and especially less of the people who use to walk around a lot, everywhere getting what they deserve by going on the acid.

https://gtm.steamproxy.vip/ugc/2021593941281380266/2E664A16AA597A8D87D003650266723C460B5682/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Then, take the water barril, make sure to put a lot of water on the stripper room. The room must be filled with the more water possible for everyone to die instantly, and none of them getting the time to call ambulance. This is the most difficult part because it's very tricky. But if you success killing the bodyguards with no alarms, the rest is quite easier.

https://gtm.steamproxy.vip/ugc/2021593941281389639/7076D03873879C61DF589599407D1F6A6BB9B56E/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

If you didn't know about the stripper :

• Take the water barril on the truck outside
  
• Go to the room with the poster, this is the room to fill with water
  
• Refill the barill with the water on the room below this one
  
• Call the stripper by looking the poster
  
• Once there are no eyes on bodyguards anymore, you can walk around them freely, putting even more water and activing the fountain trap when they're all on the room.

To be sure no one will see the burned corpses, take them all to the down right corner of the room. Less chances for someone simply passing on the big room aside to see them.

https://gtm.steamproxy.vip/ugc/2021593941281390749/D65F4EB1C16EBDA82839860C874FC864DC08449C/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Then, you should attract, one by one, the people of the room below. Don't kill them with your capacity since, as you've seen it before, it triggers the alarm instantly. You can use alcohol to make the useless girl and boy to go away from there so you can kill the 3rd guy, put its corpse with the burned corpses and take its pass so you are not forced to kill everyone if you don't want to. But, really, since there is not a lot of people now, it's not that difficult.

Other littles tips that you may know :

• Every person sleeping should be carried right to the acid path for them to sleep better and deeper.
  
• Boombox to place on the front of the two big yellow trucks to attract most people and then kill them with the trucks
  
• Boombox can also be placed on the acid path. But if you already have the 42 walkers killed, you shouldn't have a lot of people to attract there.

Since it can be long to wait, I advice you to train yourself how to electrify all the guards without triggering the alarm before doing the wait trick.
Who would have guessed that even without your intervention, at least 42 people would have died disappeared in this party ?