Continuity mistake: When Peter comes down to answer the phone, he's wearing a blue shirt. When he hangs up the phone, his shirt color changes to a light red/pink color. Then back to blue again.
Deliberate mistake: During Peter's party, when the girls start to gather around Peter to try and convince him that he's not dull, there's a closeup of Peter that's a flipped shot. Additionally, when everyone runs out for the fire drill, Peter's striped tie is tied very differently - it goes from grey/gold at the top to burgundy at the top.
Answer: The dangling bracelet was used for dramatic purposes - to keep the audience on edge.