If I remeber correctly heart extraction and chain reaction are the 2nd awaken skills that can't be canceled with shadow dash. So you could use them at the end of your combos when assassination is on cd. I don't know how heart extraction will behave against enemies knocked down by heart thrust or final destruction. Maybe this will help. It's the same person. You can watch his other videos if you want. Or just ask yoowy to stream combos on twitch if he can.