Cops can control their environment a lot more than “you don’t know what’s behind a door.”
They can wear armor, can use their legal powers to compel people to act, can call for backup, can kick in doors, can call in helicopters, can get intel about the enviroment or suspects via the legal system, can have advanced weapons that most people can’t easily get I.e tanks/full auto guns, can restrain people, access to immediate and free healthcare and sickeningly have near full immunity up to an including murder, on and on.
All of these let them control an enviroment, much like an electrician can toggle off and tag a breaker. Both are in dangerous situations that have tools to mitigate that danger.
These tools must mainly work too, as police are not even in the top 20 most dangerous careers in the US. They rank under pizza delivery. The kid in a hat with a box of pizza that has none of these advanced tools to protect them.