At 22:25, it sounds like Rebbe is describing Tzo'an Mitzrayim rather than Bel'a/Tzo'ar. I don't recall which shiur, but I really enjoyed the comparison of the destruction of Sodom and 'Omara to that of Yericho. The negev region (mentioned in the first half of the chiasmus) and the kikar that hosts Sodom and 'Omara as far as Tzo'ar (featured in the second half of the chiasmus) are linked, with Yericho as a replacement for Sodom/'Omara, in Devarim 34:3 וְאֶת-הַנֶּגֶב, וְאֶת-הַכִּכָּר בִּקְעַת יְרֵחוֹ עִיר הַתְּמָרִים--עַד-צֹעַר. These shiurim are wonderful!