As of 4/20/19 the servers are now back on!
You can get this achievement in 1 minute.
To get this achievement set up a boosting party of at least 2 people (the game is completely dead).
On the main menu press online and then select Private Match (Private, Ranked, and Player all count). I personally picked a Stock mode as it is quicker. The map does not matter.
When the match starts have the person losing walk off the map 3 times. This will unlock the achievement for the winner. Now simply repeat the steps and both people will have the achievement.