Kernrechtsfrage
Whether the 2 June 2005 stair incident qualified as an accident or equivalent bodily injury under UVG/ATSG.
Extrahierter Entscheid
No. The evidence did not establish with predominant probability that an external harmful factor occurred; the most likely explanation was an internal 'giving way' episode during ordinary stair climbing.
Extrahierte Begründung
The claimant gave inconsistent versions over time; the earliest statements were not sufficiently specific, and ordinary stair use is not an unusual external factor. A mere internal knee collapse does not satisfy the accident requirement.