Evanston argued that each gunshot causing injury – or each individual victim – should be treated as a separate “occurrence” under the policy. That interpretation would have required the sheriff’s office to pay a $500,000 self-insured retention (SIR) for each occurrence before Evanston’s coverage would be triggered, potentially leaving the sheriff’s office responsible for millions in out-of-pocket costs before any insurance payout. The sheriff’s office, however, contended that the entire shooting incident should be considered a single occurrence, meaning only one SIR and one $500,000 annual aggregate deductible would apply.