ND52 Keyed Privacy Lock

Lever with key cylinder outside; push/turn button in lever inside; deadlatch
In unlocked state latch is retracted by either lever
Outside lever is made inoperative by pushing button or pushing and turning button on inside lever; key outside does not lock
Pushed button unlocking: key outside or rotating inside lever retracts latch and releases button unlocking outside lever. Closing door also unlocks, preventing lockout.
Pushed/turned button unlocking: key outside or rotating inside lever retracts latch but does not unlock outside lever; rotate inside button to start position to allow button release and unlocking by key or by rotating inside lever
Inside lever always free for immediate egress