A shadow covered the arena as an array covered the entire visible sky. The spectators' minds shut down as they tried to process what they were seeing, while the competitors were trying to absorb the fact that Lex was completely unharmed by the previous bombardment.
Lex on the other hand, was thinking of ways to endlessly increase his firepower while making his array as precise as possible.
He also had to give a large part of his focus onto the array itself as well. While the characters that formed arrays were found in the universe, making them reappear was not magic. Lex had to expend his own spiritual energy to form them, which is usually why when he formed arrays they were close to his body. After all, the shorter distance his energy had to travel before forming the characters, the less energy he would have to expend.