At the end of sequence 3, you will unlock the first rift missions. These involve gathering fragments of data in a set location to reach a certain amount of points in an allotted time limit. Once you collect the minimum amount of needed data, a trapped assassin will be revealed and you will have to get to him and free him using
before escaping through the portal to end the mission. Do this 10 times to unlock the achievement.
This does not have to be done on different missions for it to count. I had only unlocked the first two rifts and you can simply switch between the two or keep playing the same one over and over until you pop the achievement. I recommend the tornado one as it's less frustrating than the debris constantly flying around the bottom level on the other mission. Replaying these missions is also a good way of earning quick cash and along the way you should be able to get the following achievement by playing through the rifts: