Everyone had different expressions on their faces when they saw the arrow that flew over.
Dayus was shocked and doesn't know what to make sense of the situation. Because he knew that the Squad doesn't have any lightning elemental users and he is sure that this is not the way they used to attack.
Brother One is nervous and afraid. The first thought that came to his mind is that he clearly gave the order to withdraw and not attack, but the attack still came. But after the initial shock, he realized what Dayus realized and started thinking rapidly about who this might and both of them came to a single conclusion.
It is Sam. It has to be him.
As for how he did this, they have no idea.
This time, it didn't happen because of the high-level intelligence gather Sam usually does, rather it was extremely simple and straightforward.
When Brother One is desperately trying to call squad 2, they were unable to pick up, because they were in a battle.