Slitherine

If an extended line has a 2 base wide gap behind its centre two bases, can it drop to tactical and fit through when it makes an outcome move? Or would it have to stay in extended line and burst through the friendly troops behind each outside base of the extended line?

I am assuming since page 64 says a unit may 'pass through any gap wide enough for a small unit' that the extended line can drop the bases back as long as none move more than a base width.

Confirmation from anyone??