[quote=@LeeRoy]
No clue what you're talking about when you say anomaly of physics.
[/quote]

Your character moved with the spikes momentum to escape the trap, but their momentum was ultimately pointed inwards, unless he thrust himself out with a push they simply would have pushed his hands in and pierced him regardless because his body wouldn't suddenly fly out of the trap, instantaneously. That being said, even if he had pushed himself out he would have ultimately lost his lower body, as the spikes would already be too close together by the time they had reached his hands, they'd definitely be finished forming the point of the cone by the time the rest of him escaped. 

Don't get caught up on the name, the earth 'pillar' doesn't have to be a pillar at all, its shape is completely up to Metz in the bounds of the diameter and height.

Unless for some reason you're having trouble visualising a two foot by four foot cone of spikes.