Psychopaths are in such devastated arrested development, that it is very difficult for them to reconsider impulses, to put the brakes on. An individual psychopath’s position on this continuum is one of the great deciding factors between failed and successful (passing) psychopaths.
Elsewhere I have suggested it might be possible to pin down a sociopath’s approximate age level (somewhere in the latency period) but their development is a very odd amalgam with certain almost infantile traits. The above is one, another is their inability to differentiate between the self and the self’s emotional desires (to them these are not two things). Being emotionally thwarted is taken to be an attack on the self. [Emotionally/psychologically it “hurts” them.] Source.
Rep. Grimm’s presuming the camera is off with the interview being over is also consistent with psychopathy. This very shallow, not all possibilities entertained, thinking is very typical of psychopaths and children.