  The canonical pulsar magnetosphere contains a bubble of closed magnetic field
lines that is separated from the open lines by current sheets, and different
branches of such sheets intersect at a critical line on the light cylinder
(LC). The LC is located far away from the neutron star, and the pulsar's
intrinsic magnetic field at that location is much weaker than the commonly
quoted numbers applicable to the star surface. The magnetic field surrounding
supermassive black holes that reside in galactic nuclei is of comparable or
greater strength. Therefore, when the pulsar travels inside such regions, a
non-negligible Lorentz force is experienced by the current sheets, which tends
to pull them apart at the critical line. As breakage occurs, instabilities
ensue that burst the bubble, allowing closed field lines to snap open and
release large amounts of electromagnetic energy, sufficient to power fast radio
bursts (FRBs). This process is necessarily associated with an environment of a
strong magnetic field and thus might explain the large rotation measures
recorded for the FRBs. We sketch a portrait of the process and examine its
compatibility with several other salient features of the FRBs.
