At first, when the 2nd year teams that were now led by Serhan arrived behind the mother tree. The concentration of beasts wasn't much, but as time went on it began increasing.
This was because it was hard for the beasts to reach the humans within the range of the mother tree. So, the next best option was getting those that were outside its range.
The pressure on the combined 2nd-year teams had more than tripled. They were beginning to find it hard to prevent the beasts from overrunning them even with all their fusion spells.
Seeing that getting overrun was inevitable, Serhan decided to go ahead with his initial plan. He instructed the group to slowly move into the range of the mother tree.
Using mana manipulation to create hard surfaces. The group easily got past the quicksand and move into an area covered with thorny plant vines.