Stealth is that thing that like, I dunno, ninjas use. And even while Allenby had that job, she was not very ninja-like! Rather she, and her Moogle Carol, are more than happy to face the monster head-on, already Carol prepping Allenby with a haste spell.

With the creature staring down the taunting Bartz, Allenby has a change to run over and just slut it right upside the head!