Active Shooter Question

I live a few hours from Allen, TX and am very familiar with the outlet mall and have been there numerous times. Never really thought about this until today and now I really don’t know how I would respond.

So, here’s my question…if you are in an active shooter situation and chose to shelter in place. Would you draw your weapon to be prepared in the event that things go sideways where you are sheltering in place or do you remain concealed until you know that the threat is imminent?