i bought back in on the news yesterday but am wondering if we've...

i bought back in on the news yesterday but am wondering if we've all been sucked in here. Merck were already on the hook for milestone payments, of which there seemed to be very little detail on when they were due and why, but these were priced in to the stock by analysts along with future licensing deals. Questions I have are:

1. Are the Merck shares diluting?
2.why shares when they should have been providing a payment?
3. Why a premium to merck? Ordinarily a cornerstone investor would get s discount.
4. Is this just a pump and dump?

I'm thinking of selling ASAP as have been caught out before.