  Only recently, complex models that include the global dynamics from dwarf
satellite galaxies, dark matter halo structure, gas infalls, and stellar disk
in a cosmological context became available to study the dynamics of disk
galaxies such as the Milky Way (MW). We use a MW model from a high-resolution
hydrodynamical cosmological simulation named GARROTXA to establish the
relationship between the vertical disturbances seen in its galactic disk and
multiple perturbations, from the dark matter halo, satellites and gas.
  We calculate the bending modes in the galactic disk in the last 6 Gyr of
evolution. To quantify the impact of dark matter and gas we compute the
vertical acceleration exerted by these components onto the disk and compare
them with the bending behavior with Fourier analysis. We find complex bending
patterns at different radii and times, such as an inner retrograde mode with
high frequency, as well as an outer slower retrograde mode excited at different
times. The amplitudes of these bending modes are highest during the early
stages of the thin disk formation and reach up to 8.5 km s-1 in the late disk
evolution. We find that the infall of satellite galaxies leads to a tilt of the
disk, and produces anisotropic gas accretion with subsequent star formation
events, and supernovae, creating significant vertical accelerations onto the
disk plane. The misalignment between the disk and the inner stellar/dark matter
triaxial structure, formed during the ancient assembly of the galaxy, creates a
strong vertical acceleration on the stars.
  We conclude that several agents trigger the bending of the stellar disk and
its phase spirals in this simulation, including satellite galaxies, dark
sub-halos, misaligned gaseous structures, and the inner dark matter profile,
which coexist and influence each other, making it challenging to establish
direct causality.
