bryandollery
And, you can't quit all application servers at the same time. These are distributed, self-healing, and highly-redundant -- meaning that there are thousands of copies of each service, and the system will bring up new copies to replace the ones you kill, without loosing service (though you could, potentially, affect quality of service).
Even the control mechanisms that allow all this magic to happen are run on the same platform, meaning that you can't affect the managers in this way either.
The sort of things you can do are: affect billing and reporting, find sensitive company data, and, potentially, execute code remotely (though that will probably be in a container, and not have access to much else).
Grabbing source code is problematic. There is more than one repo -- in an org this size there are probably millions. The code is huge, so downloading it will take forever, and then you'd have to read it. Finally, it's written in dozens of programming languages, some, like Golang, are unreadable to anyone but experts.
And, really, dictators don't need help imprisoning dissidents -- it's sort of in the jobspec. It's not likely that a vuln would cause this to happen unless it was in systems created and secured specifically for sedition, in which case a researcher should be considerate of the potential damage.