for a second i thought you mean 4" deep i was like "WTF are you doing typing on your computer!!!" but then i saw the part about it being a shaver. also, if the blood gets on your clothes, wash it in COLD water, if you wash it in hot water you will be able to see a part of the stain forever.
not true, you could take 3 blades of a saftey razoer and stack them on top of each other (just the very end that is) and it still would be sharper than the sharpest kitchen knife. shaving razors are VERY sharp, they are also very though, facial hair is very strong for its size, try shaving with the sharpest kitchen knife you have, will never happen.
watched a show on the history channel about blades, about 2/5 of it was about shaving razors