'Grey's Anatomy' Sneak Peek: Why Alex and Jo Might Miss Their Own Wedding

It wouldn't be a Grey's Anatomy wedding finale without a little drama.

With Alex (Justin Chambers) and Jo (Camilla Luddington) set to tie the knot during Thursday's season finale, fans should expect things to not go smoothly. In fact, if a recently released sneak peek is any indication, the wedding might not happen at all.

You can watch the sneak peek here.

In the sneak peek of the big finale episode, released by E! News, Jo and Alex decide to have a quickie before the ceremony in a shed on the property where the wedding takes place — while already dressed — but when the door to the shed won't open, things get awkward.

"Can't you just kick it open again?" Jo asks her husband-to-be.

"I kicked it in," he reminds her as he struggles with the faulty door knob. "It doesn't move the other way."

As it becomes clear that they're trapped, Jo comes up with the only feasible back-up plan she can think of: "I'm going to scream now, OK?"

As she and Alex shout for help, Jo begins to wonder about the efficacy of their yells. "Can they hear us?" she wonders.

"Definitely," Alex reassures her. "They definitely hear us."

Jo and Alex have had quite the journey to the aisle. After his failed marriage to Izzie in the early seasons, Alex and Jo started dating in season 9.

The couple hit a roadblock at the end of season 12 when Jo rejected his marriage proposal, afraid to reveal she had changed her name and was still married to an abusive man she had run away from years before.

The couple took a break after Alex nearly ended up in jail after he beat up DeLuca (Giacomo Gianniotti), thinking he was sexually assaulting her while she was passed out drunk. And their relationship was again tested when Jo's estranged ex wound up in the hospital in season 14 and ended up dead.

Jo surprised Alex earlier this year when she popped the question after an emotional case that reminded the doctors of their first love.

The episode will also see Bailey (Chandra Wilson) begin to re-evaluate some of her decisions in night of the stress she's been feeling for the past year. Considering her recent heart attack, her husband becoming a firefighter, and a cyber security attack, the Chief of Surgery has been going through a lot.

The finale will also serve as a farewell to series regulars Jessica Capshaw and Sarah Drew, who were announced to be leaving the series in March.

Pompeo recently spilled details about her co-stars' exit, assuring fans their end won't be too distressing.

"You only get killed off when your behavior is bad. If you're a nice actor, you die nice," she explained, pointing to former castmate Sandra Oh as an example.

"[She] left in the most amazing way," Pompeo said. "She gave everybody so much notice. She knew 10 seasons was all she wanted to do and they don't get much classier than Sandra Oh. But yeah, these endings aren't tragic."

While she couldn't give away too many details about the May 17 season finale, the actress noted that it will be a "classic Grey's finale."

The Grey's Anatomy season finale will air Thursday, May 17 at 8 p.m. ET on ABC.