His double Fatality does not exist in MK3 on MAT2. It was in a earlier version of MK3 when Cyrax's Fatality used to be: FCF + RN. It was removed in the final version which is on MAT2.

Too bad for MAT2. It was a neat trick.
I think it was version 2.0 and under in the arcade, where that glitch was possible. I believe you could still do it after they changed the fatality codes.
I have this version, but I can't remember the sequence to get it to work.

i've encountered another Cyrax glitch on UMK3.. while playing as Classic Sub-Zero on the Master level, Cyrax's AI is programmed so he does his exploding teleport when u do the freeze move.. keep doing sub-zero's freeze fast each direction and hit cyrax and he'll eventually go invisible.. something in that order.. i forgot how i did it exactly, it was real odd tho