Quickly, he invested his energy into mastering non-verbal spell casting.
To go into the space of consciousness, use magic, and then bring magic into reality, was quite a cumbersome process. It took him 5 seconds the first time Benjamin attempted to finish it quickly, which was much slower than chanting the spell straightaway.
In ambushing, apart from stealth, speed is key.
Benjamin had to continuously practice this process and keep it under 2 seconds at least. Or else, even if non-verbal spell casting was highly covert, there would be a great cut to the rate of practicality.
So for this goal, he could only put in hard work to achieve it.
Thus, even if it was past 2 a.m. late in the night, Benjamin had no intention of sleeping. He was also worried about the training the next morning, and thought that he should sleep, but there was nothing to be done; practicing magic was too interesting!
