Ok, so the key here is to remember that these are werewolves, and werewolves are as tough as nails. Have them escape in a badass and bloody fashion, and it makes the players feel cool, but also impresses upon them that these are some tough creatures.
Working on the lumber mill idea, imagine if the mill is built by a river. . at the edge of a massive cliff and waterfall. The main mill is some distance from the waterfall, but the fight can range out to the edge of the cliff. Along the way, you can give the werewolves a 'tear free' power to use if they get immobilised or whatever.
The power is as simply as them taking damage in exchange for a save vs the effect or a free escape. You can describe them ripping themsleves painfully free of entangling vines, howling and shaking their head to clear a mental effect, and so on. Rather than ignoring these lockdown effects, it emphasises them- but also shows how formidable these creature are, and how much pain and punishment they can take (and how angry it's getting them at the pcs).
So you start the fight however you want, preferably with a scare- they could chase a few bandits in there, hear screams inside, and go in ready for battle, only to find the bandits hanging from the rafters of the saw mill, eviscerated. Build the tension for a moment, with noises and glimpses of something climbing over the battered old roof, peering in theough the gaps- and then have the werewolves smash in through the walls and ceiling, and attack.
Of course, they're only toying with their prey, but as these are PCs, so they're bound to get a tougher fight than they bargained for. Move the fight staedily along the map to the cliff edge, using the 'tear free' ability when you need to.
Then, when you juge it's a good time to finish, the alpha of the three can look at the moon which is sinking below the horizon, howl to the others, and, with menacing backward glances that speaks volume of future conflict to come. . .
They jump off the frikking cliff!
After all, they're werewolves. Is the lake below made of silver? No. You could even let the pcs catch glimpse of them erupting from the water on the distant shore of the lake far below- or just wreath the whole area below the cliffs in fog. Let the howls follow them to the manor, and let the fight be a real "this isn't over" moment.