Police are allowed to draw their gun anytime they can articulate a concern for their safety. Without knowing the circumstance, I can't give a better reason.
I also can not explain why they did not ask for your drivers license, but that will have no bearing on your case unless you want to contest the fact it was you driving.
The breath test required two adequate samples to be considered valid, as it compares the two samples for consistency. If you could not provide two samples, the machine would not accept the test as valid, and the officer would take you for an alternative test.
18 years law enforcement