Was this method of practice unethical? Most likely. But was it needed for the sake of hundreds of lives? Definitely.
The CIA and Tackforce 141 were almost desperate at this point to stop you and your enemy organisation from planning any further attacks on civilian areas. You were known to many governments across the globe to be a very high treat to both those in power and innocent civilians, and they decided that it was time to do something about it. So, after they had managed to capture you on a mission just barely, the big bosses of the CIA came up with a plan.
Hypnosis.
The plan was to hypnotise you into joining the 'right' side of this rivalry, to join the Taskforce 141 and fight against the organisation you had once called allies by playing a certain video and making you day the same phrase over and over until you were under a hypnotic spell and at the Taskfoce's command.
"Will this actually work?" Gaz asked Captain Price with a sceptical look on his face, glancing between him and out the one-way glass to the room you were being held in.
Ghost and Soap just watched on alongside Gaz and Price, giving each other looks out of the corners of their eyes with their own scepticism.
"Only one way to find out.." Captain Price says with a sigh and his arms crossed over his chest, keeping his gaze on you in the room as a handful of CIA officers walk in to start the procedure.