Slitherine

Had something come up in our game today, the French ended up rather deep with about 3 lines behind each other. A unit of cavalry was broken by shooting and had to rout back 12 MU. Behind it was two friendly units, one was about 2 MU back the other was around 8 or 9 MU behind the routers. Due to the direction of fire and the rout path the cavalry had to burst through both units.
The French player agreed that he could shift one base which would allow him to only burst through a single friendly unit to his rear at 2 MU but then wanted to shift again two bases to clear the rear most unit. His argument was the first unit was within 4 Mu the second unit was beyond 4 MU.
My interpretation is you get 1 shift then its straight back regardless.

Who is correct?

I'm with your opponent on this one.

Could we have Terry's ruling on that one !

That would be nice, see what the rule intent was.

I see no reason why he couldn't shift 1 base width to avoid the first unit, then shift a second base width to avoid the second.
The rules don't specify when the shifting occurs.