A lot of great thoughts and information.
What I've taken from the discussion is:
1) The obvious: get yourself (and friends/loved ones) out if possible without putting self/them at risk. No brainer. Interesting tidbit I picked up from the news last night: they said the mall went into "lockdown". Not sure how soon after shooting started or if it happened after shooting stopped. Could that mean that at some point people couldn't get out of the mall while the shooter was still active? That could really change the thought process if you know that the doors may be locked before you could get there.
2) If you cannot safely get out, the best move would be to try to get to a safe, defendable area and take cover. Again a no-brainer.
3) Many replies confirmed my initial thoughts: drawing a weapon out in the open in such a chaotic situation is probably a bad idea unless ABSOLUTELY neccessary. Going on the "offensive" (towards the shooting or after the shooter), while it may be brave, is just not smart. Too many facotrs can work against you once you make that decision. It's an individual choice as to whether it is worth the risks.
I appreciate the feedback.