The progress Zheng achieved was meager. He was still losing mana rapidly. There was still much work to be done. If his focus was already at 100 percent, it had now increased to 200 percent. His efforts were restricting the flow of mana, but it was meagre progress. He still lost mana rapidly.
When he made progress and was about to run out of mana, the Dream Bison next to him would resupply him. The process continued, and six mana fruits were consumed.
Zheng was getting frustrated with his progress. He wanted to stop the training. He didn't like the sudden feeling of being energised and fatigued that came with replenishing and draining his mana.
All his focus was on the training, and it was pushed to its peak. Hence, he could barely think. But he managed to think.