Having this structure for my final answer about How to finish a run in 10 minutes:
See the tile right above the Solar Chamber? You can build a road to connect it, while the key is that: just don't. For the big guy will smartly take the very first passable path towards the orb instead of the shortest way, which means building extra roads may cause about 5 more minutes at worst waiting for him wandering around the whole map.
……Seriously.
——dspzzy