Leo does have a 450 base. But I'm not going to let that stop me! Ability Activate! Not Applicable: (Haos Switch! I choose to replace your Gate Card. Then, Haos Switch opens it at twice it's effectiveness. It's Switch Element, so you're going to be changed to a Ventus Bakugan, stopping your Aura Chain from working!)
Instead, I'm going to activate an Ability Breaker to stop that card (Assuming that falls under Battle Rule #12).
I have one turn to counter. So, instead of playing a counter, I countered a different way.
So...uh...let's get one thing straight here. I don't know what you're trying to say by the first sentence, but I hope it means that you can't do what you just did, because you can't.
Haos Switch is a normal ability, and Petra has prevented you from using normal abilities; therefore, Haos Switch cannot be activated. There is no such thing as having a one turn grace period in this instance; it never existed, unless you care to enlighten me on when that became a thing.