Being outnumbered and alone is a nerve-racking situation for any warrior.
If your warrior is fighting alone against two or more opponents, and there are no friendly models within 6" (knocked down, stunned or fleeing friends do not count), he must make a test at the end of his Close Combat phase. The test is taken against the model's Leadership on 2D6.
If the warrior scores equal to or under his Leadership then his nerve holds.
If the score is greater than his Leadership, the warrior breaks from combat and runs. Each one of his opponents may make one automatic hit against him as he turns to run. If the model survives, he runs 2D6" directly away from his enemies.
At the start of each of his turns, the warrior must take another Leadership test. If he passes, he stops but can do nothing else during his own turn except cast spells. If he fails or is charged, he runs 2D6" towards the nearest table edge, avoiding any enemy models. If he reaches the table edge before he has managed to recover his nerves, he is removed from combat.