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Option 1: Gek was an Oban, and his execution immunity triggered.
Option 2: Gek was a Raven, and his execution immunity triggered.
Option 3: Gek was one of the other mafia members, and he was saved by an ultimate ability. It's unlikely that Nebok would have added any description just for that.
Option 4: Gek was a Narodar, which is also doubtful. It doesn't quite fit with Gek's gameplay.
Option 5: Gek was a Master. This is also highly unlikely, considering there were no visible attempts to share information from his side.
Option 6: He was Imaris. There's a chance, considering his strange nighttime actions.