On flt. 20 NRT to MSP last Monday (7th) had a character light up a smoke in the rest room about half way to MSP! Alarm went off etc. A couple of pilots finally got the door open (guy would not open the door for FA) and spend some time discussing the matter with him. Wonder what they do to someone in a case like that??? Hope he was at least banned from future flights...he appeared as if he was also "out of it" !! Probably should not have been allowed to board in NRT..But NRT does not appear to be overly organized.