Makoto used her taunt 3 times that raises her power, then used tanden reki which EXTREMELY raises her power then ibuki takes more damage when she is in juggle state!
Really what happened to get it to kill ibuki in 2 hits has to do with what ibuki did. Not just with what makoto did. The juggle state has nothing to do with the huge damage.
Basically you’ll notice right before Makoto lands the first punch on Ibuki, Ibuki dashed forward at her. Now that dash was not her regular dash. That was her special move dash that forces her to take an extra 50 percent damage when hit during the dash. That plus Makoto fully charging her taunt and activating super equals 2 hit death.
Ibuki actively doing a special move is the other half to why this combo works. This combo probably doesn’t even kill akuma.
You can also kill Twelve in two hits by Makoto while he recovers from XCOPY. Akuma has the most infamous one-hit kill in 3S thanks to XCOPY.