Indeed.
Why did he assume that the boss only concealed second stage monsters? If it had the means to hide their aura from him earlier, then it must surely have had the means to hide those of the third stages.
Before he even knew what was happening, the third stage monsters had started rushing him. And Vacuse did the only thing he could do....
.....he turned around and fled into the forest, crushing all the second stage monsters that stood in his way.
There was no reason to stay behind and try to take on a group of third stage monsters when he could separate them and take them one by one.
By running into the forest, he created an opportunity to separate them. And he did not hold back, he pumped power into his legs and his speed increased, throwing him forward with blurring leaps.
