Checking If Session Has Timed Out?

This is my base class for all pages except EndSession.aspx

override protected void OnInit(EventArgs e) {
base.OnInit(e);
if (Context.Session != null)
{
//check the IsNewSession value, this will tell us if the session has been reset.

[Code]....

But on EndSession I try to navigate back to, say default.aspx, and then this code above just redirects be back to EndSession.aspx.

So for better clarification:

Step 1: Go to mypage.aspx
Step 2: Wait for timeout
Step 3: try to navigate away
Step 4: get redirected to EndSession.aspx
Step 5: try to navigate away
Step 6: GoTo set 4
Setp 6 should be actually being able to navigate away...