From SRH:

A pilot on short call is required to be within the general area of his base and promptly available for contact by
Crew Scheduling, and must be able to promptly report for an awarded/assigned rotation. Since each base has
its own particular traffic problems, the phrase “promptly report” has never been defined in terms of time or
distance, and is based upon normal circumstances that can be expected throughout the day or night. Actual
realistic response time may vary from base to base and with weather and time of day. It is not possible for a
pilot to anticipate and account for abnormal conditions beyond his control, which may extend response time
beyond that normally required. For example, a NYC pilot encountering a snowstorm or an LAX pilot caught in
rush-hour traffic might each require more time than normal to sign in.
Occasionally SC assignments may report very shortly after the SC begins.

I don't answer the phone in the bathroom or while driving. Scheduling's panic reaction is beyond my control. Sorry I DON'T answer the phone.