That's what I thought, but seriously. Who would make a topic about that?
I get it now, The middle wasn't frozen all the way.
Stabbing the ice caused immense pressure to continuously build inside it, then a little bit later,
POW.
Happened to my science teacher. He was holding a glass pane when he dropped it on the edge of a brick, put it didn't break, just a small crack on it.
One hour later, SMASH.
He had no idea what happened, until he figured it out later.