"Alright," Maudre said in a nod, smiling at Amy. She then walked over to a far corner of the room, took in a deep breath, at starting muttering some kind of spell under het breath. While doing so she extended her arms in front of her, holding them out as if she was holding a small, invisable ball between them.
After a couple of moments of this she raised her voice, and while she did so her arms spread, as if the 'invisable ball' she seemed to be holding was growing in size. By the end she had her arms wide-spread, and she was still speaking in a slightly raised tone. Then, suddenly, she stopped, and both her voice and her stance returned to normal. There had been no detectable magic, not visable, hearable or even sensible, and to anyone who didn't know Maudre's magic capabilities, it would've looked as if she'd just failed epically at whatever it was that she'd been doing.
Maudre seemed pleased though; she turned around to Amy and explained: "I only have one portal in this room, so I had to make another - otherwise I can't travel from the one to the other after all. She then closed her eyes, inhaled calmly, then said in a soft but clear voice: "prosus."
For the first couple of seconds, it seemed like nothing was happening. All that betrayed the spell had worked was a low, buzzing noise that came up, louder and louder as the seconds went by. A keen eye would notice that Maudre's extremities (her fingers and toes) had started to disappear; it was like she was disappearing molecule for molecule. By the time most of her fingers had disappeared the phase at which this happened started to speed up rapidly; the next second, most of her arms and legs had disappeared, and also a little bit of her nose.
While the disappearing sped up, the buzzing sound got louder too. Also, the atmosphere in the room seemed to be getting electric. You could see tiny sparks flying back and forth metal objects that were near each other, and Amy might also notice her hair becomming static.
Then, one blink of the eye beyond this, Maudre was less than a torso and half a head, and within the next micro-second she had completely disappeared.
Amy might in the mean time have noticed something happening on the other side of the room too, by the other portal; with every particle of Maudre disappearing in the one place, one appeared again across the room. So as soon as Maudre had disappeared in the one place, she'd completely reappeared in the other. At this exact moment, the buzzing stopped as well, rather abruptly.
"There," Maudre said cheerfully, as if it was nothing, "piece of cake."