This was hardly surprising!
From the very beginning, their plan had been to inflict as many casualties as possible and reduce the enemy's numbers before the two sides erupted into all-out chaos. There were plenty of Dark Wizards entrenched in Hogsmeade, so naturally there was no reason to let them off.
Of course, everyone had been itching for a fight too.
They had been held back by Albert before and never had many opportunities. Now that an opportunity had finally come knocking, they all wanted to try out what they had learned from Albert.
There was no grand conspiracy involved in the whole process. They were simply using their advantage of striking first to exploit the enemy's lack of information.
They deliberately triggered the Screaming Charm to lure the Dark Wizards entrenched in Hogsmeade over to investigate. Then the three squads swarmed them and easily took out the enemy.
Next, they used the commotion from the battle to draw in the Dark Wizards nearby.
Then, with absolutely no sense of fair play, they launched another ambush. After taking down the second group of Dark Wizards, they used several Flashbangs to lie in wait for the third.
After all, no one would have expected some shameless wizards to throw Flashbangs at them. While the enemy had been blinded, they launched another surprise attack and took down a whole batch at once.
Losing more than twenty people in just a few minutes completely panicked the Dark Wizards, who had originally held the numerical advantage.
Most tragically, the Dementors they had finally called in for help ran straight into a team where most people could use Patronuses. They were savagely ganged up on by a large number of Patronuses and fled in disgrace.
The remaining panicked Dark Wizards stubbornly resisted under the cover