I don't know a lot about animations. I think yea you will need to see behavior files. What would happen if you add the perk through a magic Effect(would only work for player) and attach a script on the effect? There's this mod called Better Vampire NPCs where the vampires with blink perks can teleport behind the opponent when hit. You can also look at the vanilla mage Orchendor who can teleport when damaged. Looking at how both of these work can give you some insight as well I think.