Well... I don't know. To my mind, there's a difference between "leaning into" & "standing up to". Yes, I believe you may be able to lean into a panic attack... to encounter it... to sit within the vortex as another member wrote here on PC a day or two ago.

You can perhaps lean into a panic attack, breathe into it, perhaps even smile to it with as much compassion & lovingkindness as you can muster. You might even place a hand over your heart as a sign of acceptance for it. As the 11th century Tibetan Buddhist yogini Machig Labdron said: "In other traditions demons are expelled externally. But in my tradition demons are accepted with compassion."

At least to my way of thinking, standing up to a panic attack the way one might stand up to a bully is a different image. To me, that implies force & rigidity. Perhaps something like that might work for some people. I personally think it sounds scary too. It would not be a technique I would be interested in or would ever try to use.