I'm not sure that article is useful to your point, as it states that the Sheriff's office was claiming they were blocking the hospital, but that "The Independent could find no evidence of them blocking emergency exits."
> While the sheriff's department said protesters at one point blocked entrances and exits at the hospital, no videos or photos confirmed that was the case.
[snip, most of the article about the shooting itself]
> Rather, video footage showed a handful of deputies standing in a driveway (apparently an entrance to the hospital’s emergency room), while the small group of protesters paced up and down a sidewalk feet away from them.
> At one point, deputies detained a journalist with LA’s NPR station, KPCC, who was reporting on the small protest, as well as a male protester who “refused to comply” with deputies’ demands to leave the area.
> The sheriff’s department said the reporter, Josie Huang, ignored deputies’ repeated commands and did not present “proper” press credentials. But she said and videos of her arrest show she didn’t have time or space to react to deputies orders before they shoved her and forcefully took her into custody. In one video, she can be heard shouting “I’m a reporter… I’m with KPCC” as officers push her to the ground. They cited her with obstructing justice, though KPCC is urging authorities to drop the charge.
Adding onto this to say that the LA Sheriff's Department has less than zero credibility when it comes to any matter concerning either race or protests against police action. They literally have violent and racist gangs operating in that department. There is a reason why "Google LASD Gangs" has become a meme in LA and LA-centric circles of the internet. It is a known problem and almost no one in power is working to fix it.