A perfectly fine set of trauma shears costs $5. You can throw them away if they get rusty after a couple of years, but they still work fine even if rusty. They will cut pretty much anything better than a knife, and you are unlikely to injure yourself or damage your gear. They are also much better doing little topside jobs as well.
Years ago, in Mexico, I tried to cut a zip tie off of my regulator with a BFK, which led me to learn where to get a tetanus vaccine in Cozumel!
A backup Trilobite is a good idea too.
Seriously, unless you are a spearo, what is the advantage of a knife?
