I was watching the Oklahoma-Texas blowout so I didn’t see this happen live, but it is pretty funny and comical. So I don’t know what was going on in this play to set this up.
It looks like it was some kind of bootleg set up for a pass, or the pocket collapsed and Navy quarterback Keenan Reynolds was running for his life. He is holding the football like he is planning on throwing it and he doesn’t seem to be running away from the lineman chasing them. He seems to be running horizontally, towards the sideline, like he is trying to make a throw downfield or out of bounds.
A referee tried to get out of the way but wasn’t able to move quick enough and ended up finding himself in the way. As Reynolds closes in he sticks his hand out to brace for the impact and ended up delivering quite the stiff arm as the referee falls to the ground.
[h/t] Bleacher Report