Heyheyhey... I think the zombies were trying to say that Dr. Seok is 'eve', meaning his blood can kill the virus or something... 😱😱😱 . The higher ups know there's an 'eve' for 'adam's but don't know it's actually Dr. Seok... To stop others from knowing about this they killed the previous Dr. and cut the zombies' tongues... 
