Proceed through the mission until you leave the air vents, and a cutscene will begin. Hold Select to skip the cutscene. Stealth kill four enemies, and then disposed of the final enemy as desired. After defeating the last enemy, pause the game.
ZZ-CT is a 3x3 method proposed by Chris Tran. It is a variant of the ZZ Method with a unique 2 look LSLL, divided into TSLE and TTLL. TSLE inserts the last edge whilst orienting all corners.
There are several styles of UPS tracking numbers. 1Z tracking numbers are of the form 1Z xxx xxx yy zzzz zzz c, where xxx xxx is the alphanumeric account number of the shipper, yy is the service code, zzzz zzz is the package identifier, and c is a checksum of some sort. mike has worked out the checksum, and has a tool online to check it.