The Secret Service’s job is not to protect the President.
That’s second on the list.
The first job of the Secret Service is to protect themselves.
A bodyguard isn’t much use if they are easily beaten in a fight. Or if they are too tired to notice a threat.
Their first job is to look after themselves, to work on their skills and health and ability to ensure their environment is as safe as possible.
Unless they ensure that they are safe and strong and ready, they are in no position to help anyone else.