Iya Kazurashi Bridge
Located in Japan the history of the Iya Kazurashi Bridge is a mystery as no one knows who actually built it. There also exist other bridges similar to Iya Kazurashi. It is believed that the bridge was contrasted by people who wanted to run away from the Genji Clan.
Iya Kazurashi Bridge is made of ropes and wood. Seemingly it was made in such a way that after crossing it, the cords could be easily cut to destroy the bridge and so prevent attack from the enemies.
So just imagine crossing a bridge that the builder had no intention of it lasting and could be used as a way to fight an enemy. I believe you have the answer to that.