Greenwood doubles up

Jon Lynch limped in middle position and Mark Greenwood checked his option in the big blind. The flop came down J 2 8. Greenwood checked and Lynch bet 4000. Greenwood raised all-in for an extra 15k. After much thought Lynch made the call with K J only to find he had let Greenwood in with a big blind special of 8 2. Turn 4 and river 6 gave Greenwood the double-up.