I can't ever see myself doing it, but I think it is possible for a superb swordsman to recover from a seven foot lunge. Florian is still at an advantage because of the distance he has to recover, but it is not impossible.

[quote=@Vordak]

However, you have yet to address the fact that as soon as Florian's hand leaves the grip to grapple, Brennus can easily push his sword downwards and threaten him with the tip pointed to the face.
[/quote]

I don't think he can do that, due to the way he's parried. This could work even if Florian parried with one arm: Brennus' weak is firmly against Florian's strong. Florian's sword is horizontal, tip to the left, while Brennus' attack is a straight lunge. Even with six hands, he couldn't push down on that. 

It occurred to me another thing Florian could do here, as he has complete control over Brennus' blade, is shift his sword so the tip faces Brennus. This pushes Brennus' blade away and lets Florian stab him unimpeded.