Help with Liu Kang Dragon Tail Amp

[Mah ♥♥♥♥♥]

So there is this combo with 3 + 3 + 3 then amp B , F + 3 AMP, then B,F +3
I try this combo tons of time, but about 70% of the time , the AMP won't come off.
I tried several characters, and I feel like for Liu Kang, this combo is harder to pull off because the combo and the special move share the same key (3)
Maybe I am doing something wrong.
Anyone is experiencing this issue?

[noprod]

Try pressing block just before you hit 3 where they practically are pressed at the same time. It will come out. Liu Kang is one of the easiest characters to play, his combos aren't hard to execute but once you get the timing right, it's a breeze.