Dark ops challenge Fatale.

What the fuck. I just had my 3d attempt at this calling card going solo. 1st try used my HE-1 and didnt got it. 2nd attempt failed. And 3d just 10min ago I tried it with a handcannon and like the first try got them down exactly at the same time but again didnt got it! Its driving me insane. What am i doing wrong? I wait until round 30+ to have them spawn for the first time with 2. Do i need to use a sniper bullet? Only way i didn't tried. For fucks sake. It doesnt help that i lose to patient 13 the 2 attempts that worked in my book. And when it failed. You guessed it. Was when i took it down. I need some advice here.