Bach: Ach Gott, vom Himmel sieh darein, BWV 2

This morning I listened to Bach's Ach Gott, vom Himmel sieh darein, BWV 2.  At the beginning of the fourth movement, there's a wrenching accidental on the second syllable of "verstört" and the accompanying violin part:

(notation found here)

I had to look up "verstört" to understand the reason behind that accidental though.  "Die Armen sind verstört" translates to "The poor [people] are distraught."  Those tonally-abrupt accidentals audibly demonstrate that agony.