Grievous was not content with simply keeping the Padawans as prisoners and soon began preparations for a grand experiment involving the young Jedi. In the Anoat system, Grievous and the clan made a brief stop on Gentes, an Ugnaught world. Tak-Tak watched as Allara, the de facto leader of the clan, stood up to Grievous managing to snatch one of his stolen lightsabers from his belt. She and the rest of the clan were quickly subdued however by an impressive display of the ruthlessness Grievous was capable of unleashing. Gathering an entire city's population together, Grievous had the city razed from orbit, killing all in the attack.
Following this, Tak-Tak and the Jedi were taken to the moon of Belsus and kept in a holding cell on Grievous' base. There he continued plans for the experiment he wished to conduct on the Padawans. Using himself as a model, Grievous developed similar, metallic exoskeletons for Tak-Tak and the other Jedi to wear. Grievous planned to use the Padawans to build an army of Force-sensitive warriors married to the technology that made him such a powerful foe. Grievous believed that such beings would be all but unstoppable. Unfortunately, the procedure required Tak-Tak and the Jedi to sacrifice organs and limbs as Grievous had, a horrifying fate.
Within their cell, Allara led Tak-Tak and the clan in an effort to find a way out. Using their limited skills in the Force, they were able to discover tunnels underneath the cell carved out by an underground, Ugnaught resistance movement. When a member located the Jedi, he helped them navigate the tunnel towards freedom. When Grievous discovered the Padawans missing, he went on a rampage and carried out the search himself. Deep within the caverns of Belsus, at the lowest levels of the complex, the Padawans made their way across stone bridges that spanned rivers of magma. This is where Grievous caught up with them.
Luckily for the Padawans, a team of Jedi searching for Grievous had learned of their capture and hoped to locate them in their hunt for the General. Lef by Jedi Master B'Dard Tone, the team consisted of Flynn Kybo and Tone's apprentice, Codo Ty. On the heels of Grievous, they located the Padawans a split second after the general. While Flynn Kybo and B'Dard Tone engaged Grievous, Codi Ty used the distraction to hurry Tak-Tak and the clan to safety aboard their ship. While Master Tone and Flynn Kybo would die in the attack, Codi Ty managed to return Tak-Tak and the entire Bergruutfa Clan to the Jedi Temple at Coruscant.