Perhaps it is because I am on a call, but here are my options from the lock screen, as well as when I'm in the dashboard.
The camera is only available once I'm in the phone. The camera icon is missing from the lock screen as well as the control center from the lock screen. 🙁
It's because the camera needs use of the microphone so won't allow it whilst on a call. Same as if you play music, then open camera the music will stop playing.