  Using numerical holography, we study the collision of a planar sheet of
energy with a bounded localized distribution of energy. The collision, which
mimics proton-nucleus collisions, produces a localized lump of debris with
transverse size $R \sim 1/T_{\rm eff}$ with $T_{\rm eff}$ the effective
temperature, and has large gradients and large transverse flow. Nevertheless,
the postcollision evolution is well described by viscous hydrodynamics. Our
results bolster the notion that debris produced in proton-nucleus collisions
may be modeled using hydrodynamics.
