While there is no shortage of ways to kill Residents in First Class Trouble, anyone playing a Personoid will want as many tools at their disposal as possible to take them out. The Overdose Syringe is an item that can only be used by the Personoids and is a quick and quiet way to silence someone. Here is how to get it and use it.
The Overdose Syringe has a chance to spawn in all levels of the game but is guaranteed to generate in the second round of each match. While Residents will need to see the machine that dispenses them, Personoids will have an onscreen prompt pointing its location to them.
When a Personoid walks up to the dispenser, they can interact with it and grab a Syringe. This will take a few seconds to do, so be sure that no one else sees you. Only Personoids can grab Syringes, so if you see someone interact with a machine, stay away from them and tell the others.
After a Personoid has grabbed an Overdose Syringe, they can walk around freely with it equipped without worrying about others seeing it. It is not until you use it that the item will be revealed to others.
To use the Syringe on someone, walk up behind them and hold the prompt on the screen. Hold it for the duration, or you will let go of the player early, and they can call out to their friends. Also, you do not need to grab players to use the Syringe.
Once the bar is filled, the player will drop dead, and your Syringe will be used up. You will need to grab an additional one to use on another.