  We study the evolution of the dynamics across a generic first order quantum
phase transition in an interacting boson model of nuclei. The dynamics inside
the phase coexistence region exhibits a very simple pattern. A classical
analysis reveals a robustly regular dynamics confined to the deformed region
and well separated from a chaotic dynamics ascribed to the spherical region. A
quantum analysis discloses regular bands of states in the deformed region,
which persist to energies well above the phase-separating barrier, in the face
of a complicated environment. The impact of kinetic collective rotational terms
on this intricate interplay of order and chaos is investigated.
