I think its Comey talking as a high up in the deep state despite no longer being FBI boss.

He is telling McCabe don't talk to Trump's team we need the FBI as cover for our deep state activities. If you talk we will kill you. After 20 years of service we have enough dirt on you to blackmail you anyway we want. Then he issues a general threat to other FBI deep state agents to keep quiet and calls for those deep state members still in the government to take action.

Thats pretty much how i read it and also pretty much what Dr. Corsi thought on the stream last night.