. . . So you were roleplaying a mentaly handicapped Orc that slipped into the water and drowned? That is truely the most funniest thing I have ever read!

No, he was roleplaying an illiterate orc - an orc that can't
read. An inability to read is not an intellectual disability.
Knights were even known to have fallen off into puddles and drowned due to being unable to lift themselves.
Uniform for world war one - woolen/cotton clothing.
And soldiers drowned in the mud because they weren't able to lift themselves out of it.
It's little to do with the weight of the armor, and more to do with the exhaustion/injury of the person.
If you are an experienced horseman, and you fall off your war horse while charging at full pelt into battle, it is quite likely that you were injured.