Extensive videotape of Minneapolis riots and invasion of 3rd precinct here.   You know, like fall of US Embassy in Saigon and attack in Iran.

1. Shredding of files
2. Securing side arms, rifles
3. Chemicals, eg tear gas
4. Computers and their hard drives

Looks like all cops pulled out with all of their patrol cars.  Was anything important left?  My guess is yes.

1.  Always always some stuff gets overlooked.
2.  Perhaps the precinct has an evacuation plan, but doubt there were any drills or refresher courses because such evens are, fortunately, rare.