That does look like an IL archery tag. It does look like they should have been able to get apart.
A guy that I work with has some pictures of 2 bucks locked up, that an out of state hunter shot up in Cahoun county during gun season. The bigger buck stabbed the other one thru the neck with his mainbeam. The smaller one almost returned the favor. His mainbeam was pushing on the other ones neck. If his mainbeam would of been a few inches longer, they would have killed each other with similar wounds.

I will see if he will let me borrow the pictures to post.