Reach the southwest lobby of the Departure Building

Your first stop is the Departure Building on Spaceport, which can be found near the middle of the map, just west of the Launch Tower.

Since you'll be visiting the southwest lobby for the next part of the quest, we'd recommend approaching the building from that direction anyway.

Find the staff locker room

The staff locker room is located in the southwest lobby on the bottom floor of the Departure Building. The door is along the back wall in this very dark lobby and will clearly state "Staff Room."

As expected, it leads into another room filled with lockers and hazmat suits. The next step of the quest requires you to look around this room for some clues.

Search the room for any clues of the saboteur's identity

Look for the hazmat suits near the back of the room, then interact with them to receive the Flushing Terminal Key. Make sure you pick it up and add it to your inventory, as it's required to complete the quest.

With this new key in your possession, you'll need to leave the Departure Building and make your way to a familiar entrance to some underground tunnels.

Reach the tunnels below the Spaceport

If you're working on this quest, you've certainly already visited the underground tunnels on Spaceport for previous quests. If you recall, the best way to get below is to enter via a collapsed section just below the Launch Tower.

Once you're down here, you'll have one final task to complete.

Use the key on any Flushing Terminal to override the bypass protocol

You'll need to find a Flushing Terminal in the tunnels and interact with it to finish up the quest. There are multiple terminals you can interact with down here, but the easiest to find is just to the west of where you entered the tunnels.

When you've interacted with the Flushing Terminal, you'll be done with The Stench of Corruption and will be free to extract. There are a variety of extraction points you can reach by exiting the tunnels, so just pick the one that feels right for you and get back to Speranza.

Arc Raiders "The Stench Of Corruption"