That's when they understand that they have to start fighting their peers and talking with the big boss to get their P1 ticket moved in front of the other P1 tickets.
Otherwise he knows he's 6th in line.
The day came when, after prolonged hand wringing and with stern observations about great power and great responsibility, the priority could be set to P0. But like any bunch of junkies we came off this new high all too quickly and the P-1 classification arrived, the showstopper of showstoppers.
In hindsight what I most regret is that we stuck with an integer field; we were denied the expressive power of fractionally critical issues.