The din of excited chatter grew as the crush of UC San Francisco medical students put on their white coats and distributed picket signs saying “black lives matter" Wednesday, instructing one another to tag their Tweets and Instagram photos #WhiteCoats4BlackLives.

But at 10 minutes past noon, when the group laid down in unison in front of the medical school’s library on Parnassus Avenue, it was eerily silent. Many students closed their eyes. Some held hands. Passers-by stopped to watch and police officers lingered in the background.

More than 100 medical students participated in the “die-in” at UCSF Medical Center, lying down as if dead just outside the doors to the hospital. They joined the wave of protests following the grand jury decisions in Ferguson, Missouri, and New York not to indict white police officers involved in killing unarmed black men. These students were emphasizing how racism affects health care.

“Our oath demands that we act not only as scientists, but as concerned citizens. We have to care about all the things that stand in [our patients’] way, including racism and violence,” said Nicolas Barceló, a fourth-year medical student and an organizer of the event.

Racial discrimination is a key factor in stress-related chronic health conditions like diabetes and hypertension, according to academic research, and contributes to mental health issues in minority communities.