There’s nothing like a stomach-turning dissection to kick of TGIT! ABC's “Grey’s Anatomy” began episode 4 on a grotesque note as Richard (James Pickens Jr.) slices into a brain during the Season 12 installment, titled “Old Time Rock’ N Roll.” While cutting in the mushy organ, Richard causes one of the interns to toss his cookies. But the newbie wasn’t the only one to feel sick to his stomach during the Thursday night installment.

Maggie wakes up from her wild night completely mortified when she learns that she slept with Andrew (Giacomo Gianniotti), Grey Sloan’s hot new intern. She warns her sexy slumber party guest to be careful as he leaves the house seeing as though she doesn’t live alone. But as sly as Andrew tries to be, he bumps into Amelia (Caterina Scorsone).

Of course, Amelia isn’t able to keep such exciting news to herself. So on the carpool ride to work, the neurosurgeon blurts out that Maggie slept with an intern.

“Intern? Maggie, what intern? Meredith (Ellen Pompeo) questions. But Maggie is too horrified to spit out a name -- especially in front of Alex (Justin Chambers), who reveals he’s less interested in talking about the girls’ sex life and more worried about finding out what time he should arrive for the sisters’ dinner party, which they admit to forgetting about.

But their dinner planning gets put on the backburner when Grey Sloan announces that a “silver flood” is about to rush the hospital. Interns (and viewers) later find out that “silver flood” is code for when a swarm of old people enter the hospital. The medical crisis of episode 4 involves a party boat crashing, which injured several elderly patrons aboard the ship -- including a sweet couple whose story ended tragically after one of them died in their sleep.

In fact, a lot of patients met their fate due to the crash in episode 4 -- so many that the interns were tasked with breaking the gut-wrenching news to family members who lost a loved one. (Owen [Kevin McKidd] instructed the newbies to do this after he witnessed one intern horrifically flub revealing the death of a patient to his son.)

But when Meredith learns that Owen gave the interns the green light to become the bearer of bad news, she decides to give them some insightful advice (much better than Owen’s four-step grief process).

“You are changing this person’s life forever. You are responsible for this moment,” she saying before interjecting her own personal, heartbreaking story about how she went from a wife to a widow in an instant. “Take that seriously. And recognize the importance of your role. And respect that that person’s pain is the biggest thing in the room. Got it?”

But things only got more emotional on “Grey’s Anatomy” when Stephanie (Jerrika Hinton) reveals a painful memory from her past. In episode 4, Amelia orders a certain protocol for a patient that would require the recently operated-on woman to walk. The doctor explains why getting out of bed will be the patient’s best chance to heal. But Stephanie notes that she’s “not comfortable” with partaking in such traumatic treatment. In fact, she even tries to switch patients with Jo (Camilla Luddington), which baffles Amelia.

“What possessed you to abandoned the patient? I chose you,” Amelia asks.

That’s when Stephanie explains that when she was 5 she battled a disease that required her to endure painful treatment, which she constantly fought against despite it being for her “own good.”

“And so sometimes they would strap me to the table,” she says. “I felt like I was being punished for something that I didn’t do. And I’m not going to do that to someone else. I’m sorry. I can’t. I won’t.”

Jo can’t believe the jaw-dropping story -- literally. She even goes as far as to tell Amelia that Stephanie made the whole thing up. Livid, Amelia hunts down Richard to reveal Stephanie’s unethical ways. But Richard already knows the truth -- and questions Amelia about why she doesn’t. After all, Stephanie is her right-hand woman.

Turns out, Stephanie is a survivor of sickle cell disease; she just kept that aspect of her life a secret. “I only tell people I can trust,” Stephanie notes.

This then causes Amelia to reevaluate her relationship with Stephanie (and us to reevaluate our feelings toward Jo).

But not all of episode 4 was filled with heartbreak. Maggie dishes to Mer details on her “hot, hot” night with Andrew.

“Meredith, there was so much sex,” Maggie says before questioning how she ended up in bed with an intern. “Who does that? Who screws the intern?”

“The father of my children!” Mer quips back before asking Maggie if she thinks she’s the first person to have “inappropriate work sex.”

“We all do it. all over the hospital,” Mer reveals.

And it looks like that tradition carried on in Thursday’s installment. When Andrew attempts to apologize to Maggie for “crossing boundaries,” the two decide to be professional and end their relationship. They seal the deal with a handshake -- but of course, being that this is “Grey’s Anatomy,” a handshake turns into a kiss and the next thing you know, scrubs are flying off.

The episode ends with all the surgeons back at Mer, Maggie and Amelia’s house for their dinner party. And of course, what’s a dinner party without a little drama? Callie (Sara Ramirez) shows up to Mer’s house with her date -- the very same woman who was working at the hospital the night Derek (Patrick Dempsey) died.

Suddenly, Mer has a flashback. "It was my job to save him," she hears a voice saying.

"Grey's Anatomy" airs Thursday nights at 8 p.m. EDT on ABC.