This is an interesting point, IMO. According to page 32, lining up ASAP is only applicable to the TZ "...most directly in front". In my example it is 2's TZ. This gives us a legal solution:
Step 1. Column AB moves straight forward as it begins its move in 1's TZ. In this particular case, AB enters into 2's TZ BEFORE contacting element 3, so...
Step 2. AB lines up ASAP as per rules and finishes its move until front contact against 2. Bingo!!
Technically, AB hasn't deviated from a straight move because the EMTLU is additional to anyone previously done. I love it
And about what would happen if AB should be facing its own rear edge if lined up to 1, a new reading of the sponno priorities was needed. If you can contact an enemy front edge by moving straight ahead, you CAN move closer to your own rear edge. Only if no enemy is available around you, the move is cancelled.