Firstly, what a great minifigure. When I finished building the Brick Bank, even before I had conceived of Legonium, I went looking for this figure. I just thought she would look great standing on the roof and looking like she is up to something cool but shifty. Her official title is The Jewel Thief and she came in the Series 15 Collectable collection, along with a grapple-hook gun and stolen diamond.
On this page, the character hears a sound and turns herself (you can't just turn in Latin, you have to turn yourself or be turned). I wanted that turn to express something of her skill and agility. I went looking for a suitable adverb and found perniciter. Pliny uses it to describe how the baby Hercules seized the two snakes that were sent to kill him. Catullus uses it to describe how the young dance at weddings. The Oxford Latin Dictionary defines perniciter as 'with quickness of movement, nimbly, speedily'. I prefer to think of it as 'like a ninja'.
Suddenly she, a sound having been heard, turns herself like-a-ninja. She looks around but she is able to see no one. Perhaps Pico is here.