Prime

Prime is appearing as a corpse at Dot's Diner at Jury Street Metro Station, but only when you answer correctly to the 3 terminals in the Museum of technology. The three terminals are recognizable by the #001 #002 and #003 option at the bottom of the options when you enter terminal. From the outside, they look like any other computer terminal on the wall. First terminal will have #000 for option, and when you past that, it'll change to #001 so you could start this kind of a mini game. The key here are prime numbers. After you answer all 3 terminals across the museum of technology, you will be awarded with a key to a safe in the museum, and will be told that Prime will wait you at the Dot's Dinner at Jury Street Metro Station. When you get there, you'll find a sweet Xuanlong Assault Rifle in his corpse.