A support manager’s worst nightmare is a sub-standard support experience. Nothing scares them more than the thought of a customer storming away because the agent took too long to get to their support request. So, to put their worries to rest, most helpdesks allow for emails to be escalated in the event of an SLA violation.
When an escalation happens, it’s the duty of the manager (or whoever the issue was escalated to) to find out why SLA was violated. If it’s the agent’s fault, the manager (or even the CEO) shouldn’t hesitate to jump in, apologize and solve the issue.