Honestly though Scirocco has a newtype power advantage over Gabriel I'd think plus how do you really prepare for The O's hidden arms especially when you don't know about them. Gabriel could put up a fight but Scriocco, while arguably as good as a pilot as Gabriel, has a better overall machine, and newtype ability. 

Also I don't know about Gabriel's own beliefs as he never explored them too deeply into this roleplay. Besides Paul would just point out Puru could wipe the floor with them if they all attacked together and while Graham would understand that this is Gabriel's fight Paul wouldn't and neither would Puru. Paul's a military man and he's in a situation where he can easily win. Puru thinks the big scary guy in the weird looking suit is a threat and they should kill him.

The only way to realistically pulled out Gabriel and have him go with Scirocco or have him challenge him to a duel where both trade their respective blows and Scirocco's extra arms put him away in a quick strike.