Jessica, I'm so sorry to hear about this unfortunate event but am so glad to hear you were there and were able to rescue little Tweetsum before a tragedy happened.
There's no way for us to know that everything we put in their cage is 100% safe, and I know you always want what's best for your birdies, so don't blame yourself or focus on the "what ifs". The important thing is you were able to remove the clip.
Julie did well in suggesting you post a picture in the Dangerous Toy List, perhaps by doing so you can save another little one like you did your Tweetsum.
Let us know how she does, I hope she's just fine and recovers from the experience well