I would probably get some shucked oysters, drain out the liquid, pat them dry, bread them and fry them, then serve on a bun with tartar sauce and a side of slaw.
Oh, and take the reserved liquid, add a little water and boil it briefly to sanitize it, then dose it in the keg.
Or I might get the oysters and steam them, then serve them on the half with a little lemon and tabasco, maybe some butter. Use the steaming water the same as above, dosing in the keg.
Once you have a feel for the quantity of liquid you want to use, then just toss it in at the end of the boil to save yourself the trouble.