  We present (sub)millimeter imaging at 0.5'' resolution of the massive
star-forming region G358.93-0.03 acquired in multiple epochs at 2 and 3 months
following the recent flaring of its 6.7 GHz methanol maser emission. Using SMA
and ALMA, we have discovered 14 new Class II methanol maser lines ranging in
frequency from 199 GHz to 361 GHz, which originate mostly from vt=1
torsionally-excited transitions and include one vt=2 transition. The latter
detection provides the first observational evidence that Class II maser pumping
involves levels in the vt=2 state. The masers are associated with the brightest
continuum source (MM1), which hosts a line-rich hot core. The masers present a
consistent curvilinear spatial velocity pattern that wraps around MM1,
suggestive of a coherent physical structure 1200 au in extent. In contrast, the
thermal lines exhibit a linear pattern that crosses MM1 but at progressive
position angles that appear to be a function of either increasing temperature
or decreasing optical depth. The maser spectral profiles evolved significantly
over one month, and the intensities dropped by factors of 3.0 to 7.2, with the
vt=2 line showing the largest change. A small area of maser emission from only
the highest excitation lines closest to MM1 has disappeared. There are seven
additional dust continuum sources in the protocluster, including another hot
core (MM3). We do not find evidence for a significant change in (sub)millimeter
continuum emission from any of the sources during the one month interval, and
the total protocluster emission remains comparable to prior single dish
measurements.
