How exactly do you distinguish a routine technical glitch from a Severity 1 (Sev1) disaster that demands an immediate, "all-hands-on-deck" response? Furthermore, a Sev1 incident is defined as a critical outage where a core business system is entirely unavailable, potentially leading to massive financial loss or reputational damage. Why is the ability to trigger a rapid, high-pressure escalation the most vital skill for a production support engineer?