Since we were never given an official confirmation on Will's height, I'll use 170 cm as a lowball. 280 pixels = 170 cm
This is 1.64 pixels per centimeter
Distance between Will and the arrows before he intercepts them = 110 cm
Distance Will moved = 367 cm
(3.67) x (68.58) / (1.1)) = 228.8 m/s, or Subsonic+