It is not in the video clip..... but just before the ball is snapped, the BoxLBer (#32) shifted from out in the field (basically, where Cain ended up running to) to smack-dab into the middle of the field.
Why? IDK
Good chance there was a miscommunication - - - - and that #32 was supposed to be the outside support (and, if he stayed where he initially aligned, he can easily get out to Cain before he heads upfield).
If #32 was indeed responsible for that job, and #94 (the DE) knows that he is supposed to be out there, his job (#94) may very well be to take on that lead blocker (Miranda) so as to prevent him from getting out and onto the LBer (#32)….. much like most DL play in the Iowa system (taking on the traffic, so as to let the LBers flow to the ball)
In any event, likely a miscommunication w the DE and the LB with regard to their responsibilities.