If he became accidentally sentient, we don't know how he accidentally became sentient or when he accidentally became sentient, because no fault on Picardo's part, but he's acted as mostly the same character since the EMH was activated in caretaker when he can't have been sentient.
Besides if he looks at his factory specifications, it will insist that he is not sentient and that he cannot ever become sentient, so even if he did accidentally become sentient after the ship gets turned inside out or blasted by a weird energy discharge, he wouldn't notice because it's supposed to be impossible, and he would have no faculties to notice the change.
Besides if he looks at his factory specifications, it will insist that he is not sentient and that he cannot ever become sentient, so even if he did accidentally become sentient after the ship gets turned inside out or blasted by a weird energy discharge, he wouldn't notice because it's supposed to be impossible, and he would have no faculties to notice the change.