On the season 10 finale of "Grey's Anatomy," Cristina said goodbye to Grey Sloan, Meredith stood her ground, and a new character revealed a bombshell of a secret. 

In "Fear (Of the Unknown)," Cristina (Sandra Oh) sets out to grab some things at the mall before hopping on a plane to Zurich to take over her ex Dr. Burke's (Isaiah Washington) hospital. She then has to head to Grey Sloan for her last day, during which she's performing a scheduled heart transplant. 

Then disaster strikes: There is a huge explosion at the mall that Cristina supposedly went to, and there are many casualties. People suspect that it's a terrorist attack, but no one is sure. Owen (Kevin McKidd) holds a press conference in the hospital, which is filled with injured victims of the blast. 

Luckily, Cristina never made it to the mall and avoids getting caught in the deadly explosion. Instead, she went straight to the hospital to begin the heart transplant. 

But Meredith (Ellen Pompeo) insists that someone else take care of it and puts Cristina in a cab to go to the airport. 

Catherine Avery is in the hospital, helping with the blast victims, which Richard (James Pickens Jr.) is not happy about. Her daughter-in-law April (Sarah Drew) is having a nervous breakdown about raising a child in such a scary and often cruel world. Catherine advises not let the fear get to her, and the two reconcile. 

It's then discovered that the explosion was not a terrorist act but a gas main explosion. 

Cristina then comes back to the hospital to give Meredith a proper goodbye, which includes dancing it out. 

When Cristina finally leaves, Shane (Gaius Charles) goes with her so he says he can "keep learning" from his mentor. 

Meanwhile, Meredith has decided to stay in Seattle, despite Derek's (Patrick Dempsey) presidential job offer in the nation's capital. Meredith tells him that he always thought his career was more important than hers, and she refuses to compromise. 

Bailey (Chandra Wilson) is also recommended for a spot on the board. But so is Alex (Justin Chambers), who was recommended by Cristina prior to her departure. The two will have to battle it out for the coveted spot next season. 

At the end of the hour, the new head of cardiology that Cristina hired is in Seattle. She confides in Richard that her mother, who was a prominent surgeon at Grey Sloan, gave her up for adoption as a baby. She tells Richard that she knows her mother's name: Ellis Grey. 

What did you think of the season finale? Share your thoughts in the comments below.