The golem realized that it was going to be overwhelmed soon, so it became desperate.
It threw its shield to block the first vine. Then it jumped back while shooting many bolts at Arthur in order to take him out.
According to common sense, now that Arthur had invested so much of his mental energy into the spell, he shouldn't have any other thing up his sleeve. Either he blocks with the vines like he did before, or he dodges the bolts.
Either way, the golem would be able to resolve the conundrum it was currently in. In fact, it might even be able to counterattack and still win the fight.
But Arthur ignored the bolts. He continued to push the vines to strike the golem while the bolts sailed through the air towards him.
The bolts were the first to reach their target. They struck the energy shield that Arthur had prepared with his other phantom.
