Kunti and others were so sleepy and so nervy that they could not walk fast enough.With his dear mother on his back, the twins on his hips and the other two in his arms, the great hero walked the entire length of the tunnel. There they met a man who had been stationed by the thoughtful Vidura. Then the boatman ferried them across the river and they entered the terrible forest. Distance was a dire necessity now. They hurried along with quick steps. They could trust these people as they spoke in Mlecha Bhasha used by Vidura.
Pretty straightforward narrative! An operation which defines Bheema's strength. Must have been a large tunnel to accomplish this feat!