I think it depends on the rest length. If the pole fits inside the barn at its rest length the dynamite will explode no matter which observer is seeing that. Two different observers will claim two different views.The observer in the barn’s frame will see that the pole is moving so it will fit. The observer in the pole’s frame will see that the barn is moving so it will not fit. But if the pole fits inside the barn in their rest lengths the dynamite will eventually explode.

the day and night is the best example to state that earth is moving and changing directions