Pure speculation, but I think he's being scared into flipping. Impossible to say because the NCIS holds all the cards and are just letting us see what they want us to see. Important to keep in mind that we, the public, are being manipulated.
Well Dela Cruz didn't make anyone more dead by pumping bullets into the dead or whizzing on one...does that scare you to flip. I wouldn't think so. You are right, the will only give us blips of what they want us to know.