Can you please document a scenario here? It is very important to explain what the "Escalate after XX minutes" actually means.
In the example figure above, what it means is that if the Primary On-Call Schedule does not acknowledge the incident in 30 minutes, it will get escalated to Jason Collison (this is based on the Escalate after field next to Primary On-Call). Since the figure above has 30 minutes as an example again, that means that if Jason doesn't respond in 30 minutes, it will get escalated - only this time, back to Primary On-Call.
I would love the PD folks to post a better scenario so that people don't make any basic mistakes about this while setting up escalation policies. :)