I would be tempted to just replace it and go from there, it's not likely to get sucked through the oil pump. Seriously though, the threaded insert which holds the oil plug in the pan broke loose on an s-10 four banger when I was changing oil when it was a fairly new truck, stuck a rubber drain plug in it and drove it til it died of natural causes, can't see it moving enough to interfere with anything. Seems to me since these cars have a fairly big drain plug, you could fish it out through there with a magnet "SECURELY",(and the key word is securely) attached to a stiff wire, such as a piece of #10 or 12 copper solid electrical wire.