Next week, my wife will be away visiting family for two days. I’m planning to gut her sewing room and have another tilde vault installed.

Sounds selfish to me. 

Good luck with that!

They didn't install the floor vault correctly and she falls into it.  This is enough to  snap the floor joists under a load bearing wall, which brings down the entire house.  As the dust is settling, a stray tilde floats down landing on a bare electrical wire, causing a large shower of sparks.  The brilliant flash of the sparks startles a passing driver, causing him to plow into the approaching ambulance.  The collision of the two vehicles causes one of the vehicle's tires to come off, which then ricochets off a tree and hits the neighbors gas main.  The impact is such that the main ruptures, spewing natural gas into the air.  The still hot tilde then ignites the gas, turning the entire area into a smoking crater.  As you stand there looking over the smouldering devastation in disbelief, you hear your wife mumble, "how ever are we going to explain this to the insurance company".  It's at that instant that you remember that you forgot to mail the insurance payment last month (like she told you), thereby canceling your insurance.

Hide the scissors and any other flesh cutting utensils.