Collision in the Key

[iref4him]

I am working a junior college game last night. White team is running a motion offense. Red team is man to man. Players are flashing and defense is running to keep up. White 32 is coming from the right and Red 10 is coming from the left. Both don't see each other. Their heads are turned and like the Keystone Cops collided in the key. Collide is not the word, but a major crash 911 impact. I had a no call. Both coaches wanted something. Red teach coach wanted illegal screen and White team coach wanted a foul for interfering with his player's movement. Both players were moving. Both players were not looking at the impending impact and did not see each other. It looked bad. Any thoughts??