It’s already exchanged hands three times, all in the backfield. The pursuit should be on him any second, and he hasn’t been able to look downfield because he’s has to watch all the hand offs and make sure he’s at the right spot. He gets the ball, looks up to find his primary, and if he can make the throw he does.
Coaches will watch film, notice how wide open Milne was, and perhaps Milne becomes the primary the next time that or a similar play is run.