Remove cleric from group, and heal by hotkey. Stay in MPG (likely), or hit up a hotzone. MPG has very few hitpoints for the xp, and is good up until 74 or so, imo (lower w/ the bst tank being higher though).
If WAR is 69 though, you should try out RSS - he can zone in, so take a look see...w/ a cleric, your bst will have no issues tanking there (mine did at 70 w/ most group gear, and a 5k mana cleric bot) XP is good there duo until you turn 78 and mobs go light blue...so, should be very good duo w/ the BST.