And if flipping is your game, you or a marketmaker can certainly "short against the box".
For you the margin is $2.50 whic makes shorting un economical. For a market maker (and it was you that brought up market makers in this example) a market maker can short naked, short against margin, or short against the box.
( shorting against the box is when you sell short and use your long shares as collateral )
There is no market maker shaking shares here. These are 5 cent shares being sold at a 25% profit for a 6 month hold.