When the Imprivata lock screen is in the front, and the user receives a call, the call always renders in full-screen mode. Zebra Voice does not support Imprivata MDA Client in guest mode.
If Imprivata is not logged in and the user continues as a guest, it always launches Emergency Dialer regardless of whether it is on the Imprivata Lock screen or Android Home Screen. This feature is available from version v9.0.23405+