The OS overrides location service settings during emergency calls

> When using Emergency SOS to call emergency services, the call may include your location, regardless of whether you enable Location Services, to allow the dispatcher to assist you.

https://www.apple.com/legal/privacy/data/en/emergency-sos/

Android has a similar feature.

There is no legislation requiring this of device (or OS) vendors, but carriers are legally required to make location information available to emergency services, and I think are even prohibited from connecting phones that don’t make this possible. So market forces effectively ensure that all phones do this.

The exception is when the call is too short to get a lock for GPS and location can’t be determined. The phone will still transmit what it can (say, WiFi proximity derived location). Worse case is fall through to carrier triangulation.

This is the correct answer.