1x4 - King Arthur & the Knights of Justice

Arthur has learned the location of one of the Keys of Truth - His own. Though getting out of Camelot to get the Key proves difficult, with the Warlord's blockade forcing Arthur and a small group of Knights to use Merlin's magical underground tunnel. Merlin is unaware that Morgana Le Faye uses her magic to discover exactly what the Knights of Justice are up to and so sets a trap near the tunnel's exit. Can this trap be sprung?