Keys
With the recent pvp changes, player killers are making more use of old school techniques to escape, remember if you are involved in war, to always have the largest ammount of different keys as your cap lets you.
Sometimes they kill players in free areas (where most oftenly happens) and then run to a place which needs a key to access, also some places like the bright sword quest, where you need a power ring to open the entrance and then a key to open a door.