(Kefka)Try warping Lara to Parn using Saphy. Then have Parn steal Saphy's Unlock/Thief staves so she doesn't use them ( they're both really nice staves ). Priorize Unlock, since I don't think she'll use her Thief staff, especially if your own units have good stats. I'm not sure if Trewd flees, but Parn moves a bit faster than him and can move twice pretty often (25%).
Sure that is effective, but if you do that, you will waste a Warp Staff use, which should be needed to get all of the treasure here as without the Warp Staff, you have no way to get the treasure.
(Neofox)Trewd indeed flees, and will easily get away unless you get really lucky (which not all of us do). That's why I make sure to capture him before recruiting Parn.
I say to steal the Thief staff between the two first, though. If you're using someone like Othin, he might end up losing his Pugi axe (or something else of value) when she uses it on him due to low magic.
That is why that it is advised to just bring Iron Weapons as you have nothing of value to lose during the battle.
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The Dancers all will flee anyway once that you recruit Pahn, so be sure to steal the extra Warp Staff before driving the enemies away.