1) No one answered because the whole team was at the InsideBitcoin conference in Vegas
2) Armory isnt crashing, it's hanging, i.e. it is caught in a n2 operation bug, which makes it take a very long time to unlock wallets in certain circumstances. This issue has been fixed. The fix, along with a wallet recovery tool, will be added to the next release
3) Usually in those cases, Armory getting caught up in a very long computation, your OS sees that it isnt responding anymore and assume it has crashed, offering you to kill the process.
4) Ungracefully closing Armory will have you rescan your tx history on the next restart, to make sure the DB wasnt corrupted (in case of an actual crash)
5) You can always try to get us on our support channel:
support@bitcoinarmory.com6) This is free, open source software. Have some patience with us, we cant just afford a 24/7 support channel.
7) In case you dont want to wait for the n2 operation to complete, restore your wallet from a paper backup.
Automatic: corrupted DB on Armory's side. Your best bet it to delete the db folder, or as you did, force a rebuild with the --rebuild switch. If it happens again, catch us on the support forums and dont wipe the db just yet, we may want to have a look at it. You can build a new db in another folder using the --dbdir switch