Someone just reblogged this and I was reminded of a couple things I did deliberately while making this that I don't know if anyone actually noticed. (Which perhaps means they were unsuccessful, but whatever; the intent was there.)
The height of the crack in the wall is very low. The implication is intended to be that he started clawing at this wall when he was much, much smaller. At this size, if the figure stood, it would nearly touch the ceiling.
The marks are mostly in clusters of 4 parallel lines, implying that he was indeed clawing. His hands are hidden from view, so you don't know if they're damaged.
His position near the center of this curve means that viewers can almost never see his face, or all of his body at once. He's hiding.
The cluster of center columns means that most of your view of him when looking straight on is like seeing him through jail bars.
The absence of rubble from the wall makes it unclear if he has just stopped momentarily, or if he gave up on widening this hole a long time ago; the seated pose also makes it clear that at least for the moment, he has stopped even trying to escape.
The curved shape of the ceiling isn't appropriate to the architecture of the actual origin of this story, but I chose it in order to make the labyrinth feel more compressed and to put the inside in a deep enough shadow that the crack would always shine with bright light in comparison, blanking out the view from the minotaur's side unless you look very very closely.
