Introduction[]
Somewhat near the end of "Surface Tension", Gordon must flee from a Satchel Charge Explosion, while crouched (With the explosive still being slower). This is a unavoidable sequence that must be passed to continue the Game.
First let's figure out the Timeframe. The Satchel Charge is C4 since it's in a package and has a Detonator.
Volume[]
A. Gina Height: 561px = 170.92cm (Should be comparable to Gordon)
Satchel Length: 127px = 38.69cm
B. Gina Height: 707px = 170.92cm
Satchel Depth: 115px = 27.8cm
Satchel Length: 420px = 38.69cm
Satchel Width: 250px = 23.03cm
Now we can get the Volume with this.
Satchel Volume: 38.69cm * 27.8cm * 23.03cm = 24,770.6cc
Typical Density of C4 is 1.72658 g/cc, meaning the weight of explosives is equal to 42,768 grams or 42.768kg.
Shockwave[]
The Overwiki states that "one must be at least 7 meters away from the charges to avoid being hurt", so I tested it out.
Gordon's Height: 138px = 170.92cm
Distance from Bomb where you still take Damage: 636px = 787cm or 7.87m
Timeframe and Result[]
Finally we get to know the Timeframe!
Explosive Type will be C4 with the weight of 42.768kg and the range will be 7.87m for C4.
Timeframe: 3.49ms or 0.00349s
and now the Distance Gordon moved is simple enough.
Gordon's Height: 570px = 170.92cm
Duct Height: 449px = 134.63cm
Now for Angsizing.
Duct Height: 108px = 134.63cm
Panel Height: 1080px
Start Distance: 8 degrees, 962.65cm
Duct Height: 63px = 134.63cm
Panel Height: 1080px
End Distance: 4.7 degrees, 1640.3cm
Distance Moved: 1640.3cm - 962.65cm = 677.65cm or 6.7765m
With this we can now get the Speed!
Timeframe: 0.00349s
Speed: 6.7765m / 0.00349s = 1941.69 m/s or Mach 5.7 (Hypersonic)
Recalculation[]
Gordon's initial position is 962.65cm or 9.6265m from the Explosive. Using this again with the same Weight we get the Timeframe of: 5.06ms or 0.00506s
Speed: 6.7765m / 0.00506s = 1339.23 m/s or Mach 3.935 (Supersonic+) ACCEPTED
Well that fell down a bit, didn't it?
Still pretty fast for a highly trained professional. Enemies might scale due to two Grunts being able to capture Gordon in an important Sequence, however they might not.