I looked into reviews of that pen and figured I would grab a couple until I learned that the guts are plastic and people are only getting about a month out of them, check out amazon, not good...
I have settled on a Boker Urban Survival knife to join my pen and flashlight in my shirt pocket.
http://www.boker.de/us/pocket-knife/boker-plus/tactical-knife/01BO911.html
I can strike with it closed and, if time permits, open it for a cutting edge.
I statrted this process after watching the video in this thread https://www.indianagunowners.com/fo...se/372430-bystander-tackles-mwag-walmart.html and speculating what I could have done in that situation.