That seems reasonable considering the costs of living in the valley. As evidenced before, the standard comp is around 120M for a high level manager in a big tech company (bonus paid by google to Levandowski before he left).
4M looks like a normal package for a middle employee.
The fact that two qualified employees, a lawyer and a security constant, getting a similar sum should hint that it is common.
Uber didn't argue anything along those lines at all in court and attempted to justify the payments with something even less believable, potential court expenses and reputation risk. You may have missed it in the article, but they effectively admitted to paying the lawyer to keep his or her mouth shut.
4M looks like a normal package for a middle employee.
The fact that two qualified employees, a lawyer and a security constant, getting a similar sum should hint that it is common.