Burned wires in the shield after intervention

Hello. This morning, for some reason, the lights went out. I climbed into the shield and noticed that the wire in the middle is in a different cell, and not as before. I unscrewed it and started to put where it was, then something happened, like flashes and wires became black, as seen in the photo. Please tell me, I called an electrician for tomorrow whether he would need to change everything or if there was nothing to worry about. Thank.