Data Corruption in Escalation Records

I'm writing an alternative escalation system to NetSuite's, in order to cut escalation times down.   It uses a custom record to define the escalation tree, and then inserts new employee records into the escalation sublist in the case based on that tree.   However, I'm finding that when I run the code, the escalation sublist isn't in the same order as it was written on the last execution of the code, which breaks the escalation code since its history is lost.   Below is an extracted piece of script that demonstrates the problem, along with the debug log that shows that between