The long awaited final episode of the series airs this side of the pond tonight and have the tissues at the ready, as it's a tearjerker. It's been widely reported that Sandra Oh was set to leave the show after the tenth season, and tonight is the final goodbye to her character, Dr Cristina Yang. This means of course she will have to say goodbye to her bestie Meredith - the pair have had their fair share of ups and downs through the years and while we have have all loved the drama of McDreamy and Meredith, it's the friendship of Meredith and Cristina that has been the real heart of the show. In typical Grey's fashion though, there's also a possible terrorist attack in Seattle going on at the same time. Of course there is.