Although the mechanism for the teeth at the start works in odd-step (agree it shouldn't be necessary), the teeth at 25,1 doesn't get freed when the button is stepped on because the teeth are pointed south instead of east. That would be an issue of preservation of gameplay that was overlooked it seems. This was probably due to the teeth not dying in the fire at 30,5. To preserve gameplay one would have to change the boots to flippers and the fire to water. Same thing on level 96 Glider and Fire. The name might become Fireball and Water. 
With the teeth moved to 20,7 it slides through the portal in a quick smooth action that definitely preserves the "gotta get outta here quick" and also doesn't need odd-step.
With the teeth moved to 20,7 it slides through the portal in a quick smooth action that definitely preserves the "gotta get outta here quick" and also doesn't need odd-step.