While the Timmy to the Rescue film was kinda lame. Timmy's clever trick to fool Martin's army was pretty impressive.
ANY scene where Mrs. Brisby, who's primary state of mind throughout 90% of the film is terrified (which makes sense, really, given that she's a mouse), pulls herself together. This tiny mouse is quite the Mama Bear. In particular there's:
Parlaying with the Great Owl in his own hollow (sure, being Johnathan's wife meant she had the automatic respect of even certain predators, but she didn't know that at the time - and neither did the Owl, at first).
The scene is an awesome moment for the production team — the fantastic artwork, the terrifying atmosphere, the awesome animation for the Great Owl — it's one of the best scenes in the movie, and the Owl himself is one of the greatest animated dragons in film.
Rappelling down from the cage in the Fitzgerald's house using a piece of string (also, the act which got her stuck there in the first place.)
Climbing up a moving tractor to try and figure out how to stop it before it reaches their home and destroys it with her son still inside.
The Shrew gets serious points for climbing right up there after her and actually succeeding in getting the tractor to stop, too.
The best part is, you KNEW it was only a matter of time, before they crossed swords, and the wait is definitely worth it. Everything from the dialogue, music, the use of dramatic camera angles, and the lighting effects combine to make what is still one of the most epic moments in animated film history.
Jeremy spends most of the first film irritating Mrs Brisby by being an incompetent Klutz. However, he is the one character in the film to directly attack Dragon to protect her. Later on, as Mrs. Brisby cries over losing Timmy's medicine, Jeremy loses his train of thought and rambles on about their effort, before taking a small bag from under his wing. He saved her from the cat and preserved what was seemingly a useless piece of paper from the scuffle, and what's more acts like it was nothing at all.
Jeremy: Oh by the way, you dropped this back there...