The Alliance poison quest happens in a tower that is Maple Story Mesos northeaster part of Westfall. The actual tower is located to the east of bridge that heads to dark shire. The quest is very similar to the Horde, there is a chest in the top that you can pick to about 175, but you first have to find a way to incapacitate or kill the elite boss to make it worth while. I wouldn't try it unless you're 24 plus and that may be hard for anyone who isn't geared up or twinkled well.