I do hope someone has submitted this question to Perry. It is an interesting one with good points from both sides. Moreover, as stated by someone above, the OP situation is one that could "easily" occur is many scenarios.
The RB is unclear at best: D6.5 and its last-minute, passing mention of a "limit" - versus the Berserker rules which potentially allows a double-timing squad 2 additional MFs after going CX and running seven hexes down a road...
And while not the same, there are two Q&As which allow a Berserker more MFs despite having already used its "maximum allowance" (for that action, that is):
Q: A4.61 & A15.43 If a squad Assault Moves, is fired on and becomes Berserk, do they immediately gain (8 minus the normal MF spent to enter the hex they entered using Assault Movement) MF to use in a Charge?
A. Yes. [Compil1]
Q: A4.63 If a unit Dashing across a road becomes berserk, does it charge in that same MPh?
A. Yes, using eight MF (three MF if wounded) minus whatever MF it has already expended. [An91; An96; Mw]
I assume the answer would be the same after making a "Minimum Move"
Many of the movement rules include an EXCeption specifically for Infantry which utilize transport during the MPh (A4.11, 4.12, 4.134, 17.2). The Berserk rules includes the EXC for wounded guys, but not for unloading passengers. As said above, it may be an intentional oversight.