The LifeHammer—a tool every vehicle manufacturer should be including as standard equipment in every vehicle made (especially those taken well off the beaten path)—can be had for about $15 from Amazon, cheap assurance you’ll be able to escape the vehicle quickly should the need arise and the vehicle be uncooperative.
The LifeHammer as purchased does not come with any mounting hardware, a puzzle they leave you to figure out. After several bad experiences with all manner of adhesives on other equipment, I strongly suggest you disregard the manufacturers claim that any sort of adhesive tape will do. For going into plastic interior panels, I’ve found wood screws self-tap easily and hold well. A 5/8-ths inch #6 screw works well in most cases, and is short enough it isn’t likely to damage anything the auto maker might have hidden under the panel.
For those of us with a Discovery, the factory-installed overhead shelf/console has a large void in the center rear. This area is too far back to be a useful location for a display or gauge cluster, has no available OEM accessories to fill it, and is an awkward place for auxiliary switches. It is an empty, sturdy mounting space that serves no other purpose and is easily accessible by both driver and passenger. Once the LifeHammer is installed, all of the original access panels, switches, and lighting remain unaffected.
Once installed, this location is easily accessible while strapped into either the driver or front passenger seats. The bracket itself is tight enough the hammer isn’t going anywhere (the roof is actually a suggested location by the manufacturer), and the entire assembly sits high enough it does not block access to the sunroof controls. Down the road, the LifeHammer bracket will help shield the glare of some custom-fabricated map lights I will be installing (for some reason, the Discovery does not come with any from the factory).