iPhone 8 Plus (iOS 11.4) is frozen on emergency SOS screen
iOS 11.4 is currently under development and you have either a developer or public beta installed on your device. Beta version of iOS are not guaranteed to work without issues.

Try restarting the device. If the issue persists, and it is hindering your workflow, it is recommended you restore the device to current public release of iOS, i.e. iOS 11.3.1.

You can share any observations and issue with Apple, via the Feedback app installed on your device.