A mechanism comprising: (a) an upper latch assembly and a lower latch assembly , said upper and lower latch assemblies being in axial alignment with a longitudinal axis of the mechanism; (b) an upper rotary latch component carried on and rotationally coupled to the upper latch assembly, and a lower rotary latch component carried on and rotationally coupled to the lower latch assembly; (c) a bumper element defining a downward-facing land surface , said bumper element being coupled to the lower latch assembly so as to be both axially movable and rotationally movable relative to the lower latch assembly; and (d) a trigger element coupled to the bumper element and the lower latch assembly so as to be movable at least axially relative to the bumper element and so as to be axially and rotationally movable relative to the lower latch assembly; wherein: (e) the upper and lower rotary latch components are adapted to move from an axially-latched position to an axially-unlatched position in response to relative rotation between the upper and lower rotary latch components in a first rotational direction; (f) the upper latch assembly defines one or more downward-facing trigger reaction dog pockets ; and (g) the trigger element defines one or more upward-facing trigger dog teeth configured for engagement with the one or more trigger reaction dog pockets of the upper latch assembly; such that when the one or more trigger dog teeth are disposed within the one or more trigger reaction dog pockets, an upward force applied to the land surface of the bumper element will tend to cause relative axially-upward displacement of the bumper element urging rotation of the lower latch assembly, with the trigger element acting between the bumper element and through engagement with the trigger dogs with the upper latch assembly to force relative rotation between upper and lower rotary latch components to induce axial disengagement of the upper and lower rotary latch components, such that continued application of the upward force and resultant axial and rotary displacement of the bumper element relative to the lower latch assembly will cause withdrawal of the one or more trigger dog teeth from the one or more trigger dog reaction pockets. (a) an upper latch assembly and a lower latch assembly , said upper and lower latch assemblies being in axial alignment with a longitudinal axis of the mechanism; (b) an upper rotary latch component carried on and rotationally coupled to the upper latch assembly, and a lower rotary latch component carried on and rotationally coupled to the lower latch assembly; (c) a bumper element defining a downward-facing land surface , said bumper element being coupled to the lower latch assembly so as to be both axially movable and rotationally movable relative to the lower latch assembly; and (d) a trigger element coupled to the bumper element and the lower latch assembly so as to be movable at least axially relative to the bumper element and so as to be axially and rotationally movable relative to the lower latch assembly; (e) the upper and lower rotary latch components are adapted to move from an axially-latched position to an axially-unlatched position in response to relative rotation between the upper and lower rotary latch components in a first rotational direction; (f) the upper latch assembly defines one or more downward-facing trigger reaction dog pockets ; and (g) the trigger element defines one or more upward-facing trigger dog teeth configured for engagement with the one or more trigger reaction dog pockets of the upper latch assembly; <EOS>