The DFT table tells you everything about what happens when a shaken unit is shaken a second time. Notice that there is a column for GO MMC and a column for Shaken MMC; simply use the right column. Usually, shaken Squads suffers casualties. Shaken Half-squad, crew and WT are eliminated. Shaken SMC are wounded. Shaken armored vehicle become abandonned. Shaken unarmored vehicle are destroyed.
There might be some module-specific variation to these general rules (Japanese, Somali, etc.)