I guess he was very secure in his mind that he was never going to be captured or killed if he kept it on his person. What an idiot.
He might have figured the flash drive was more sensitive an instrument than his body.
Or maybe he just figured he didn't care what happened after he died.
Evidently he forgot the suicide belt and substituted a thumb drive.
And we got him.....alive, but only for few minutes, and the thumb drive was the prize!!