Should General Flynn seek immunity? Yes and here is why:

  "A favorite tactic of the FBI is to accuse someone of a false statement because,  to many law enforcement officers and persecutors,  an inconsistency is interpreted as lying.  That is then used as leverage to force an individual to comply in other ways,  or to be punished for crimes that perhpas cannot be proven,  regardless of the validity.  So, at this early stage  I would suggest the request for immunity is more about skillful lawyering than anything else.  That said,  the Trump Administration better hope that's all it is."  ~ Mark Zaid,  National Security expert and attorney. 

Additional notes:  Understand that the immunity Flynn is seeking is limited to the actual words of his testimony.  He is not seeking criminal immunity.  He simply does not want his words to be used against him,  and by that,  I include words that appear to him to innocent.  

Don't forget,  the Feds got a conviction against Martha Stewart for lying,  not for the charges they had brought against her.  In fact,  they could not prove their case against.  In the common vernacular,  her conviction was sheer bull-shit.  That is what Flynn wants to avoid. 

Finally,  this particular brand of immunity will not be offered to Flynn if his pre-sworn testimony is of no value to the Feds.  A refusal to give immunity to Flynn,  means that the Feds do not see his testimony as having great value.