09 Nov 2014 11 Nov 2014
Mission 10 (The Maw)
During your escape on the Warthog in The Maw, you will come across a bridge where Cortana will tell you to stop. Continue driving to the next left turn. After that, you will see an open door on the right. Go inside and take the next right. You will find the Thirsty Grunt there. Get close to him and his story will trigger the achievement.