punctuation - How should I punctuate the "Shocked" line from Casablanca?

I'm writing something that mimics the famous "Shocked" line from Casablanca, but I can't find a good way to punctuate the phrase without it looking odd. Any ideas please?

I'm shocked, shocked, that StackExchange would answer my question.

That just looks like I'm listing all my reactions.

Answer

How about:

I'm shocked ─ shocked! ─ that StackExchange would answer my question.