Liam was enjoying the little friendly competition that he was having with Simyon in his head. He had a tally of how many more members of the Rygon Religion he had taken out over his partner. In his mind, it made him a stand-out figure, and he would stand out in Safa's eyes.
So when he saw another man wearing orange, he thought it was his time to shine and rushed off after him. He had become incredibly skilled at duplicating and throwing his swords, taking out his opponents, and he had done the same rushing off after Carl.
Liam was so focused that he didn't even have a chance to look at the condition of the cellar or what was in it, and had just thrown the sword out.
'Even though this attack won't kill him, I'll still count it as an accomplishment over Simyon!' Looking deep down, maybe it was the fact that Simyon had done a better job when it came to taking on Sha Mo.
