Eh, if SpaceX had genuinely not expected the rocket to get off the launch pad, they would not have launched it.
I expect their math was something like:
95% chance of enough engines lighting to launch
90% chance of clearing launch pad
60% chance of making 60 seconds of flight
30% chance of 2nd stage separation
15% chance of re-entry
I expect their math was something like:
95% chance of enough engines lighting to launch 90% chance of clearing launch pad 60% chance of making 60 seconds of flight 30% chance of 2nd stage separation 15% chance of re-entry