Indeed, and I participated in Die Ins with Act Up in the 1990s, at zaps and protests seeking to raise consciousness about the U.S. government's depraved indifference to the HIV/AIDS pandemic. Many of the people I "played dead" with ended up actually dying from that depraved indifference — including my closest friend.
Participating in a die in is an act of great vulnerability. I generally laid on my back, hands clasped above my chest or belly. Not a position to easily or effectively defend oneself! I guess that's why I remember such events, primarily, as frightening.
Thank you for telling the story of brave people working non-violently to defend protesters. I'm dismayed that university administrators and other leaders in your community are not already doing so.