S6·E14 Valentine's Day Massacre

Episode recap

Task: Write a 280-380 word episode recap for Grey's Anatomy S6E14 (Valentine's Day Massacre).
Constraints: Use only verifiable facts from the provided SYNOPSIS and SOURCES. No invention, no guessing, no markdown, no asterisks, no headings, no bullet points. Neutral, encyclopedic prose. Plain text only.
Target Word Count: 280-380 words.
Synopsis:
It is Valentine's Day.
Doctors treat dozens of injured people after a roof collapses at a popular romantic restaurant.
Derek tries to manage his busy schedule as Chief of Surgery.
Meredith wrestles with her new duties as the Chief's wife.
Mark and Callie team up to convince Sloan to do the right thing for her baby.
Sources:
[1] Grey's Anatomy (2005) TV-14 Drama.
[2] American television medical drama, debuted on ABC as a mid-season replacement for Boston Legal on March 27, 2005.
[3] Created by Shonda Rhimes. Cast includes Ellen Pompeo, Chandra Wilson, James Pickens Jr., Kevin McKidd.
[4] Follows personal and professional lives of doctors at Seattle's Grey Sloan Memorial Hospital.
[5] Meredith Grey is a brilliant first-year surgical intern at Seattle Grace Hospital (Note: This source says "first-year surgical intern", but the synopsis for the specific episode implies she is now the Chief's wife, so I must be careful not to contradict the episode synopsis with the series overview if they conflict in timeline, though the prompt says "use only supplied facts").
Self-Correction on Word Count: The synopsis is very short. To reach 280-380 words without inventing details is extremely difficult. I must expand on the context provided by the sources without adding new plot points.
Contextual Facts:
Series: Grey's Anatomy.
Genre: American television medical drama.
Creator: Shonda Rhimes.
Setting: Seattle's Grey Sloan Memorial Hospital.
Episode Title: Valentine's Day Massacre (S6E14).
Characters mentioned in synopsis: Derek, Meredith, Mark, Callie, Sloan.
Characters mentioned in sources: Meredith Grey, Ellen Pompeo, Chandra Wilson, James Pickens Jr., Kevin McKidd.
Drafting Content:
The Grey's Anatomy episode titled Valentine's Day Massacre takes place on Valentine's Day. During this episode, the doctors at Seattle's Grey Sloan Memorial Hospital are required to treat dozens of injured people. This medical emergency occurs following the collapse of a roof at a popular romantic restaurant.

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