Kaj still found this interesting, how eager and willing this which was, though it was far from his first willing subject it was still an odd feeling.
Entering through Kaj's portal she immediately found herself in a concrete basement without any clear means of entry or exit, clearly a safety set by the man controlling the portals.
Entering after his new subject he didn't close the portal until Child had entered after him, but as soon as she had the inspection started.
His commands to the witch were short and enough for him to get what he needed, there were tests of her abilities on various textiles and other targets, some of which seeming a tad more live than others. She were put under local or full anaesthetic if anything invasive were to be done, like him taking a look at if there were any differing factors of organs or other parts not visible from the outside. He was thorough, very, very, very much so. Nothing of her body, mind or abilities were left to question, she might even have learned something new or interesting during her stay in the scientist's laboratory. Or she might not have, he honestly didn't care about such things. Though he did take note of anything and everything such details were not really what he was after.
After the whole ordeal were done, the Witch would only have realized a few facts. Kaj rarely, if ever, slept; during the whole four-day inspection he never closed his eyes longer than to blink. After each and every procedure he had rubbed a special ointment over the scarring areas which made them heal in the matter of hours ending up leaving no scars what-so-ever.
Dawning on the fifth day Kaj seemed to finally be done, at least with this particular specimen. Taking out what looked to be a slightly thicker than normal, but rather fancy, fountain-pen he handed it to his specimen.
"Normal pen, twist off the back cap-" he started explaining as he took the back off as he instructed revealing a button of sorts. "-pull, twist and push down." As soon as he followed the end of his instructions his wrist-device left off a small blip. "I will return the favor."
Resetting the device he put the back-end back on before he handed it over to the Witch.
"You will fall 2 meters, land soft" Not waiting for her to say or ask anything he opened a portal underneath her feet, forcing her to fall downwards and out of the exit on the other side of the space-time bend.
The exit portal ended up in a small alley no more than a few hundred meters away from the house where they first met, the portal closed instantly afterwards and the witch was alone in the alleyway.
Being rather satisfied with his new findings he pulled a small cable from his wrist-device and connected it to the device on his belt, a very low crackling noise marked it's existence for a few seconds before a low volume blip marked it's completion. Now he had learned everything he needed to know from this particular gifted person, as of this time, and he now had a perfect defence against anything she could do.
Now, his next plan was simple; he had a blood-mage that had been held up for quite the time. A wave towards nothing in particular pulled another portal into existence, entering through it he was about to learn something new again; something he loved more than almost anything in the world.