Figured out

Since entering the room, Sadie had been keeping an eye on the other White Rose agent. His actions seemed a little too strange and annoying, but truthfully, she didn't think much of it.

She just kept her eye on him because his actions were bothering her. As it turned out, her vigilant behaviour led her to realize that her fellow agent had transformed his hand.

"Traitor!" Sadie exclaimed urgently, as there was no time to waste.

At that moment, the White Rose agent abandoned his position by the window and made a beeline towards Haze, a long stringer protruding from his finger. It seemed he disregarded everything else, fixated solely on impaling Haze's head.

Haze's eyes widened in terror as he could see his life flash before his eyes. Despite being a trained fighter and the attack being quite obvious, his current condition made it impossible for him to move out of the way.

The stinger approached the side of his temple, but before it reached, a hand swung down, breaking it off.