Sometimes the dragon wins. Or Balrog, or whatever it is you're fighting this week. Last weekend my saturday group had a different experience. They had to run away from a group of well positioned enemies who used the terrain to their advantage. Well it was more than that. The enemies were defending a fortress. The group was also short a tank. This compounded the problem of not having enough people to soak up the damage the enemies were doing to them. In the end they fled and looked for another way into the fortress. Retreating isn't something they do frequently. The last time involved a horde of khyberspawn. An interesting session all around. Though not a TPK.