Sinkhole

The Sinkhole is a mass casualty event that occurred when a sinkhole opened up on a street in Seattle.

Timeline
After a sinkhole opened up in Seattle, trapping Susannah Wilson under her own car, Callie and Owen were called to the site to amputate her leg in order to free her. Her husband, Danny was also down in the sinkhole with her, but he wasn't trapped. However, he refused to let them pull him up until his wife was freed. When Callie and Owen arrived at the site, they were informed by Karen Lorenz that instead of performing the amputation themselves, they needed to talk Danny through it because it was too unsafe for them to go into the sinkhole themselves.

They started to talk him through the procedure, despite his reluctance. He was able to cut through all her muscle, but when the time came to cut the bone, he struggled to continue. Owen said they couldn't make him do it and offered to go down there. Callie said she should as the orthopedic surgeon, but Owen cited her wife and daughter as reasons not to go and went himself. Once he was down, Danny agreed to be lifted out and he was taken to the hospital. After Owen finished the amputation, Susannah was also pulled out and taken to the hospital. At the hospital, Danny had a CT that revealed a small bleed, which Derek said would likely reabsorb on its own. Susannah was taken into surgery, where the residents worked together to fix her numerous internal injuries. The doctors said she'd need more surgeries once she was more stable.

Alex, wanting to escape the hatred at the hospital that came from him telling Owen Meredith had tampered with the trial, also went to the site, but was quickly sent back by Callie. However, as he went to leave, he noticed Jerry Hoffman had Silly Bandz wrapped around his fingers and began looking for his kid. He found Nicky Hoffman mostly buried in debris and pulled him out. They had to do bilateral fasciotomies in the field to relieve the pressure in his arms and restore blood flow. He was then taken to the hospital, where he had surgery. After his surgery, he was neurologically intact, but they had to wait to see how he'd do. His father, Jerry, had a minor brain bleed, a broken arm, and a cut on his face. Derek determined he didn't need surgery, but ordered neuro exams every two hours. Jackson stitched up his face, but after seeing his work, Mark made him redo it.

On-Site

 * Danny Wilson
 * Susannah Wilson
 * Karen Lorenz
 * Callie Torres
 * Owen Hunt
 * Alex Karev

Doctors

 * Miranda Bailey
 * Cristina Yang
 * Jackson Avery
 * April Kepner
 * Derek Shepherd
 * Mark Sloan
 * Arizona Robbins
 * Lexie Grey

Notes and Trivia

 * Susannah's surgery resulted in Jackson being named the Gunther, though by the time he stepped up, only he and April remained working.