Leafs Nation definitely was holding their collective breath, but thankfully Liljegren was okay and did remain in the game. Nevertheless, this was a dangerous hit and could have had a horrendous outcome.
Any way you slice it, this one was a textbook boarding penalty. Either Miller committed to a blindside hit on an unsuspecting player at a dangerous range from the boards or he hit Liljegren in the numbers from behind. Those were the only two outcomes of that play. Reckless, dangerous and warranted a penalty.