If your downstairs neighbor tells you authorities have told him to evacuate, but he does not evacuate, do you in fact evacuate?

Sounds like you are set up. I would stay and guard the beer.

Get a small model boat, tether it, throw the cigarettes in it and float it over the deepest part of the water. Guard the beer. The weasels will see the cigs, wade out, and get washed away. Then pull the boat in as the water receeds and have a party.

Maybe the neighbour is secretly coveting your beer and cigarette supplies.

Not unless I was told by the authorities.

I saw something like that once on tv. Maybe it was cops. They opened a hidrant and told people to leave until it was fixed, but it was so they could get every one out to safety so they could go in and get somebody dangerous. Are you dangerous?
Otherwise I am thinking he just wanted to see if you would be slick enough to beleive him.

I’d say “Thanks!”, lock the door, arm myself, and sit in a spot where I have a clear but well protected view of the entryway in case anyone is planning a home invasion.

No. I say stay.

And send out for pizza.

I’d stay until legitimate authorities pounded on my door and ordered me to leave. In other words, if the evacuation order is mandatory, then go, otherwise, pop a top, kick back by the window and enjoy the show.