Probably should have shifted back to Motivate Dexterity. Also probably should have been paying attention
I blame work. If it's not too late, I'd ask what kind of action it is to swap Mutagenic Auras, and then if it's something silly like a free or a swift or an immediate or an impatient action or something, let's do that. +5 to Initiative checks is sweet. Otherwise:
Rolled 1d20+4 : 17 + 4, total 21