http://vsbattles.wikia.com/wiki/File:Metal_Gear_Solid_Portable_Ops_Cutscenes_part_6 I will be assuming the bullet is fired at the exact center of Gene, making the distance he has to cross as high as it can be. Since it apppears he is standing still I will also assume he crossed that distance back again. Both in 0.01 seconds as it would obviously have to be FTE.
http://i.imgur.com/3XXDEez.jpg
Gene's Height - 180 cm (shown as comparable to Big Boss) or 1821 px
Gene's Head Height - 254.25 px
254.25/1821 = 0.139x
180*0.139 = 25.02 cm
http://i.imgur.com/21ttioO.jpg
Gene Head Height - 25.02 cm or 106 px
Gene's Shoulder Width - 211 px
211/106 = 1.99x
1.99*25.02 = 49.79 cm
Since I'm assuming he crossed this in back there's no need for any further steps other than distance/time.
49.79 cm/0.01 seconds = 49.8 m/s
Results
Gene Dodges a Bullet at FTE Speed - 49.8 m/s, Subsonic