No company would pay that sort of premium. What a company, one that knows her number, would say is, let's talk when your share price is approach half of what you're demanding.
Pure BS...I don't believe that's the case. What if the share price reaches $5 upon approval? What would Merck do then? Would they prefer to pay a $5 premium now instead of a $10 premium later? Think think think...
Your last sentence is dumb. If the stock is trading publicly at $5, why would anyone, including BP, pay $10 unless they were buying out the company? Why would they spend $10 when they can buy the same thing for $5?