Over the planned route of MH370, I don't see a reason for route 2 to be different to route 1 in the cruise phase. I also would find it highly unlikely that route 2 could be inadvertently selected AND executed. If it was, and a turn to the left suddenly ensued, why not just re-activate route 1?
If there was a plan to steal the plane, could the carefully planned "hijack route" meant to confuse/avoid radar/etc have been pre-entered into the computer as route 2, so that at the appropriate time, all that would be needed to execute would be to press a couple buttons?