I am very new to merger arbitrages and currently hold a small...

I am very new to merger arbitrages and currently hold a small amount of CXS. I have just looked at the ASX short sales and have noticed 22% of the stock is being shorted. I am a little worried although it is a all cash bid by Cephalon and Cephalon have a history of aggressive all cash takeovers. My question I would like to ask is even if Valaent is successful with their takeover of Cephalon why would they impede the takeover of CXS when CXS has a long history of successful takeovers????????