Hi Rocke and welcome. I'm glad you're ok. It sounds like the accident could have been worse.
I can't give you any insight to why your chain snapped. Perhaps it was just a bad chain.
Not everyone reads the Intro threads so I'm moving this to General Cycling where you may get a few interesting replies.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.