Scenario - Glass in the Sky:
You are have a tactical pen in your front shirt pocket. You are also wearing a belt with a holster containing a tactical light with a crenelated bezel. You managed to clear air port security with these items and they are the only things you have on your person that can be realistically used to defend yourself. After the plane has taken off, you get out of your seat to go to the rest room. Before you get to the door, a madman bursts out. He's in a rage yelling obscenities and mumbling non-sensical phrases under his breath. He has managed to break the mirror in the restroom and has wrapped a towel around the glass so that he can hold it without cutting his hand. He's waving it around in a manner that is essentially making it a slicing implement capable of inflicting deep gashes if it makes contact on soft vulnerable flesh. If he strikes you right now, he could easily slice your neck. You know if by chance, the weapon strikes you in a certain manner, it will slice your jugular. Even if someone does apprehend the perp after he injures you, you could easily bleed out in minutes and expire on the floor before you could receive appropriate medical attention.
What do you do? For the purpose of this scenario, you have to use one or the other; crenelated bezel or tac pen. You can use other things in addition to one of these items but you must use one of these items.
Disclaimer: I've never been in the rest room on a plane so I don't even know if they have a mirror the wall that you could break and use as a weapon. For the purpose of this scenario let's either say that they do have mirrors in the rest room or that the perp managed to get a hold of someone's mirror...a lady's compact, for example.
I'm looking forward to hearing solutions to this scenario.