  The co-evolution between black holes and galaxies suggests that feedback of
active galactic nuclei influence host galaxies through ejecting radiative and
kinetic energies to surroundings. Larger scale outflow in local universe are
frequently observed by spatially resolved spectroscopy, while smaller scale
outflow cannot be directly resolved by current observations. At the scale of
the dusty torus, radiative and kinetic energies ejected from the central active
nucleus interact with the materials. However, observations of such outflow are
rarely reported due to the lack detection of unambiguously gas emission. Here
we report the detection of clear and rich emission lines origin from the scale
of dusty tours in an partially obscured quasar. The lines share a common
intermediate width with full width at half maximum about 1900 \kmps\ and are
shown in two systems: a major system is unshifted and a minor system has a
blue-shifts of about 2600 \kmps. The line intensity ratios, combining
photo-ionization simulations, indicates an ultradense line-emitting region with
the density as high as $\sim$ $10^{13}~\rm cm^{-3}$. We interpret this as the
lines being excited by a shock induced by the high-density and high-temperature
gases at the scale of dusty torus, rather than photo-ionized by the central
accretion disk. We speculate that the outflow, launched from the accretion
disk, collides onto the inner wall of the dusty torus and shock-heat the gases
to cause the major emission lines. The outflowing gases may also collide onto
surrounding isolated clouds, and give rise to blue-shifted minor emission
lines.
