Just in case you ever wondered: Note, that the presenter only demonstrated the probable method of urinating while wearing plate armour, but omitted a similar demonstration of defecation. Given that diarrhea / enteric illnesses were probably a commonplace on medieval battlefields, there were probably methods of achieving that, though it has to be said, privies / thunderboxes / latrines were probably not available when the slings and arrows of combat were flying...given the weight of the armour, and the greater probability of overbalancing while squatting to crap, it is likely that one of their squire's essential functions would have been to steady their master while their master was taking a crap. As has been alluded to, when one is fighting for one's life, the aesthetics of soiling one's smalls is a much lower concern in the hierarchy of things to attract one's attention.
Advances is armor, especially in it's construction designs removed a lot of these "Issues", many a knight or Sell Sword simply had the armor trimmed back, and wore a metal cod piece which could be moved pretty easy, this is also where the button flaps started out, making it far easier to do ones doodie when needed! You also saw a lot of boiled leather lobstered in place of metal plate, and a lot of chain mail in high flex areas! The best only had armored breast plates over a chain mail parka length shirt and Lobstered Leather at the joints. Additional armor in the arms and legs was also kept to the minimum, only protecting the minimum to keep limbs attached ( mostly) but to free up the knight to be more agile, and lighter on his feet!
Polishing their master's armour was an essential part of a squire's apprenticeship. Chainmail was kept clear of corrosion by rolling it in a barrel of sand.
Maybe olive oil was used as a metal preservative along with other unsalted natural oils and greases. Jim
