This is where Zoe's collar breaks in The Great Dog Caper.
[Later that day]
Zoe Trent: I'm so excited. [is gathering some of her stuff] Manehatten, make way for Zoe Trent! [she is about to race to get something else, but she feels a jerk] Huh? What the?
[her collar is caught]
Zoe Trent: [gasp] I'm stuck! [tries to pull free but has no luck] I'm really stuck! Help! Help! I'm Stuck! Help!
Blythe: [races in] Zoe, what's wrong!?
Zoe Trent: Blythe, my collar's stuck! And I can't get get loose! Help me!
Blythe: Calm down, Zoe! I'm help you. [grabs Zoe's collar] On 3. 1.. 2.. 3! [pulls but her collar doesn't come loose] Uh, it's really stuck. Okay, again. 1.. 2.. 3! [she pulls harder on Zoe's collar, but then a ripping sound is heard as it comes off]
Zoe Trent: What was that?
Blythe: [looks down and sees a tear in Zoe's collar] Oh no.
Zoe Trent: What? What's wrong, darling?
Blythe: Your collar.
Zoe Trent: My collar? What's wrong with my collar?!
Blythe: It's been ripped.
Zoe Trent: RIPPED!?
Zoe Trent: [sees the rip] My collar! My precious collar!
Blythe: Uh, Zoe. I hate to say this, but I don't think I can take you to Manehatten after all.
Zoe Trent: [gasp] WHAT?!?!
Blythe: With your collar ripped, it would be too riskey to take you in a big city like Manehatten. If you lost your collar, then you'd be caught by the dogcatcher. I'm sorry, Zoe. But it's for your own safety.
Zoe Trent: Okay, I understand. [whimpers silently]
Blythe: [pets Zoe] I'm really sorry, Zoe. I know you were looking forward to this.
Zoe Trent: [sighs]
[Zoe sadly goes over to one of the pet stands and sadly sits on it]
Fluttershy: [comes in the room]
Blythe: I wanna thank you again for watching the pets, Fluttershy.
Fluttershy: My pleasure Blythe. have a nice trip.
Bythe: Oh also, Zoe's collar's broken so I can't take her with me. And she's feeling really sad.
Fluttershy: Oh my, I'll be sure to tend to Zoe.
[Blythe then leaves]
[Zoe is still on the perch as the others look up at her]
Sunil Nevla: What happened?
Vinnie Terrio: Zoe's collar broke.
Opal: And now she can't go with Blythe.
Sunil Nevla: [gasps]
Zoe Trent: [looks at the window]
[she watches as Blythe leaves on her motorscooter]
Zoe Trent: [sadly lays on her belly and sighs]
[the others all gather and look up at her]
Penny Ling: Zoe? Are you okay?
Zoe Trent: [Slips back]
Splinter: Poor girl.