Anger

Alex had made a mistake in his analysis, Gunther did not position himself near the exit because that was his escape route, he positioned himself near the exit to stop others from escaping. 

Gunther pressed on a switch hidden in his pocket. The switch was something he had made before just in case. It switched off the electricity flowing through the school. The entire building turned dark, and because they were in the hallways away from the windows it was darker than normal. 

Gunther was observing each of the members of the Mercenary Club the moment the lights turned off. Alex was obviously running towards Alisa who was visibly shocked by the sudden blackout. Oliver showed a shocked expression and got into a defensive stance. Rachel was confused by the blackout, while Sayaka and Niel showed no change in expression. 

Kei and Kyle who were watching at the distance took out their phones and used them as flashlights.