Hyun kicks a monster hard enough to send it flying through a wall
Hyun's height = 70 inches (177.8 centimeters) = 253.1 pixels
Hole Radius = 367.1/2 = 183.55 pixels = 1.2894188068 Meters
Hole Width = 36.2 pixels = 0.254301066772 Meters
Hole Volume = 1.2894188068^2 * Pi * 0.254301066772 = 1.32826905634 M^3
Using stone as a low end and reinforced concrete as a high end (As you can see what appears to be rebar in some of the chunks)
Fragmentation of Stone is 8 j/cc and violent fragmentation is 69 j/cc
Fragmentation of reinforced concrete is 10 j/cc and violent fragmentation is 61.2 j/cc
Stone low: 1,328,269.05634 * 8 = 10,626,152.4507 Joules, 0.00254 Tons of TNT, 9-B, Wall level+
R. Concrete low: 1,328,269.05634 * 10 = 13,282,690.6 Joules, 0.00317 Tons of TNT, 9-B, Wall level+
R. Concrete high: 1,328,269.05634 * 61.2 = 81,290,066.2 Joules, 0.019429 Tons of TNT, 9-A, Small Building level
Stone high: 1,328,269.05634 * 69 = 91,650,564.9 Joules, 0.02191 Tons of TNT, 9-A, Small Building level
Hyun performs this feat in base (We don't see any red skin or black veins that normally signal Hyun starting to turn) and is consistent with Joon Shin describing fighting Hyun as suicide, despite himself being capable of matching Wook Pyeon, who could make a large dent in a metal door with a single punch