  G0.253+0.016, commonly referred to as "the Brick" and located within the
Central Molecular Zone, is one of the densest ($\approx10^{3-4}$ cm$^{-3}$)
molecular clouds in the Galaxy to lack signatures of widespread star formation.
We set out to constrain the origins of an arc-shaped molecular line emission
feature located within the cloud. We determine that the arc, centred on
$\{l_{0},b_{0}\}=\{0.248^{\circ}, 0.18^{\circ}\}$, has a radius of $1.3$ pc and
kinematics indicative of the presence of a shell expanding at
$5.2^{+2.7}_{-1.9}$ km s$^{-1}$. Extended radio continuum emission fills the
arc cavity and recombination line emission peaks at a similar velocity to the
arc, implying that the molecular and ionised gas are physically related. The
inferred Lyman continuum photon rate is $N_{\rm LyC}=10^{46.0}-10^{47.9}$
photons s$^{-1}$, consistent with a star of spectral type B1-O8.5,
corresponding to a mass of $\approx12-20$ M$_{\odot}$. We explore two scenarios
for the origin of the arc: i) a partial shell swept up by the wind of an
interloper high-mass star; ii) a partial shell swept up by stellar feedback
resulting from in-situ star formation. We favour the latter scenario, finding
reasonable (factor of a few) agreement between its morphology, dynamics, and
energetics and those predicted for an expanding bubble driven by the wind from
a high-mass star. The immediate implication is that G0.253+0.016 may not be as
quiescent as is commonly accepted. We speculate that the cloud may have
produced a $\lesssim10^{3}$ M$_{\odot}$ star cluster $\gtrsim0.4$ Myr ago, and
demonstrate that the high-extinction and stellar crowding observed towards
G0.253+0.016 may help to obscure such a star cluster from detection.
