US Chess School's Strongest Camp Ever

From left to right: FM Vignesh Panchanatham, FM Craig Hilby, FM Joshua Sheng, FM Cameron Wheeler, GM Jan Gustaffson, IM Luke Harmon-Vellotti, IM Daniel Gurevich, GM Jeffrey Xiong, IM Ruifeng Li

The latest edition of US Chess School was led by GM Jan Gustaffsson. The camp's students consisted of one Grandmaster, three International Masters, and four Fide Masters, making this the strongest US Chess School camp in history with an average US Chess rating of 2492. 

Gustaffsson has a reputation as a theoretician, and the camp focused on high-level opening preparation. An imporant aspect of this preparation were training games in opening variations, examining common middlegame positions. 

IM Ruifeng Li vs. IM Luke Harmon-Vellotti

Middlegame #1

How did GM Jeffrey Xiong take advantage of White's uncastled king and misplaced pieces?