In this part of the film, Pongo and Perdita arrive at Hell Hall and attack Horace and Jasper, allowing Tibbs and the puppies to escape.
Pongo and Perdita's entrance is interesting for several reasons. The breaking glass in shot 72 is in rather large chunks. I hate to say it, but it looks like Blaine Gibson (or possibly an uncredited effects animator) took the easy way out by limiting the number of pieces.
Shot 75, with the dogs in front of the fire place, is one of the few expressionistic pieces in the film, where the backgrounds mirror the characters' inner emotions. That fire is an expression of the dogs' rage at anyone who would threaten their pups. This kind of thing was used extensively in Snow White: Snow White's flight through the forest where the trees are an expression of her terror, the storm as the dwarfs pursue the Queen expresses their anger and the candles "crying" when Snow White is in the coffin. Live action film continued with expressionsim during the post-war film noir period, but Disney seemed to abandon it after the war, one of the things that make the post-war features less interesting to me.
Shot 77 of Pongo, teeth bared, charging the camera is this film's equivalent of Monstro charging the camera in Pinocchio. Reitherman animated the Monstro shot and I'm sure that he recalled it when directing this sequence.
In shot 80 by Ted Berman, the pups are looking in the wrong direction. The shot is re-use from earlier in the film, but the puppies should have been flopped based on the character locations established in shot 68. This is known as crossing the 180 line and is frowned upon as bad film grammar.
The pan in shot 101 is on two's, which results in some strobing. Shot 100.1 has a pan on ones, but the animation is on two's. This kind of thing is indicative of the studio trying to hold down costs on this film.
The battle is an interesting mix of genuine action, with the dogs and the Baduns intent on damaging each other, and low comedy. Pongo knocks Jasper down and gets kicked towards a closed door, hitting with real impact. John Sibley, Cliff Nordberg and Frank Thomas handle the above. When Pongo recovers, he gets behind Jasper and manages to sink his teeth into Jasper's rear, courtesy of John Lounsbery on Jasper and Thomas on Pongo. I'm sure that there was a conscious calculation not to let the action become too intense for the children in the audience by making sure there was comedy at regular intervals.
Once Pongo bites Jasper, the rest of the sequence shades more to comedy, with additional assaults on characters' posteriors and dignity. Perdita upends Horace butt first in the fireplace and Pongo pulls Jasper's pants down. The sequence ends with the Baduns being bonked on the head by falling plaster. Knowing Reitherman, I was expecting a close-up of the two of them looking goofy from the impact, but they've got to stay conscious as the chase continues, moving from Hell Hall to the countryside.
Whatever acting is here is pretty broad. There's good action that's solidly drawn. The characters have weight and momentum. They occupy well defined spaces. However, there's little time for characters to think or register their emotions when the action is so furious.
The sequence is definitely exciting and moves the story forward. The characters are no longer searching, they're now escaping. This might be a good spot to consider as the end of the second act.