I've sub-3min'd this one so it's not as gimmicky as initially thought, though there's a "safe" way to get ~4:45. Parody contracts are love.
Accidentally Killplaned Myself (Hokkaido-PC): 1-10-5217131-02
Drown the Hospital Director as the Hospital Director. Now you could wake him up after taking his clothes, but that would ruin your Silent Assassin ranking. So you'll just have to figure out a way to drown him as him without getting caught. Easy, right?
And yes, SA is possible (the title hints at how, I'm sure most people familiar with Hokkaido already know), I wouldn't do that to anybody: