  We show that one-loop corrections to the large-scale power spectrum from
small-scale modes in non-slow-roll dynamics are always negligible, namely they
are volume suppressed by the ratio of the short to long distance scales.
One-loop contributions proportional to the long wavelength tree-level power
spectrum, and not sharing this suppression, appear only when considering a
subset of vertexes, but they cancel exactly when all relevant interactions are
taken into account. We prove the previous statement in two different ways, i.e.
by using two equivalent forms of the interaction Hamiltonian. Contributions
from boundary terms to equal time correlators are included when necessary.
