Ork Mob Rule!
(Rule)Description: If an Ork mob fails a moral or pinning check, roll 2D6. On a roll equal to or less than the number of Orks (ignore Gretchin) left in the mob than the Orks instead pass the test. An Ork mob of twelve or more models will therefore always pass these tests.
Orks falling back can attempt to regroup as normal, but may also instead fall back towards any Ork mob that lies behind their position. If any Orks in the withdrawing unit get within 6" of the new mob once moves are complete then the withdrawing mob attempts to join with the new one. Roll 2D6 again the Leadership value of the falling back mob. If successful the two mobs combing together into one unit. The previously withdrawing mob can immediately move up to 6" to be in coherency with the second unit.
Only Ork foot units will mob up in this manner. Slavers and Meks in Grot mobs or Big Gunz, Stormboyz and Warbikes may not mob up.
A mob of Orks that mobs up with another unit counts as destroyed for victory points purposes.