Infiltration is the title of a series of three Challenge missions, you are the three secondary characters of the three story missions played.
You play as Gregor Lenko in the first one, in which you play the first part of Siberia, the satellite dish area, where you have to also blow up the satellite dish. You play as Lady Jane in Chicago, at the Docks, where you have to kill everyone silently without them seeing. You play as Chastity in NeoTokyo, the streets, where you have to avoid or destroy all the cameras and reach the end of the street.
All levels give you 1000 points, if you are seen, the points will deduct.