Introduction[]
Feat in question: http://i.imgur.com/WHpsJGC.png
Calculation[]
Average lightning speed is 440000 m/s.
Budo is 1.9 m: https://akamegakill.fandom.com/wiki/Budo
An arm represents 38.65% of a male's full height, directly taken from this thread: https://exrx.net/kinesiology/segments
Budo's arm length = 1.9 * 38.65% = 0.73435 m.
Budo's arm from shoulder to finger = 270 px.
Pixel scaling = 0.73435 / 270 = 0.00272 m/px.
Distance between lightning and the ground = 585 px = 1.5912 m.
Distance Tatsumi crossed = 675 px = 1.836 m.
Tatsumi's Speed When Dodging Lightning = (Distance Tatsumi crossed*Speed of lightning)/(Distance between lightning and the ground) = (1.836*440000)/(1.5912) = 507692.3076923 m/s = Mach 1480.15 (Massively Hypersonic+)
Conclusion[]
Tatsumi dodges lightning instantly = Mach 1480.15 (Massively Hypersonic+)