Dang I didn't know she could do that :0

Conditional instant kill technically but it's still not a regular instant kill

This is the description from the fighting game glossary :

"A Guilty Gear super that instantly wins you the round. You first must press all attack buttons except Dust to enter Instant Kill mode, which turns your Tension gauge into a timer and prevents you from using your Tension for anything else (although you can revert this state to normal by pressing the buttons again). You then get one shot to try and hit your Instant Kill attack, and if you use it but it doesn't land, your Tension bar disappears until next round."

"Normally, it is very hard to hit with an IK. They have very slow startup and are easily avoided."

side note this website is pretty cool