Finally got to watch the show this AM, and though I agree that in the past seasons the moles were pretty ridiculous for a top secret government agency, the guys who got in this year might have been able to do it. Spencer wasn't really a "mole", the administration sent him to CTU with all the proper security clearances, the mole is actually the chief of staff. I could see the Toons pulling something like this, and there would be no way to block him. The assassin was signed in by a legitimate CTU officer.