After a roll-over, it won't be there and you may not be able to reach the glove box. If you have a center console, I recommend keeping it there (that's where I keep mine).
If you're reading this and you don't have one in your car, buy one now. Here is a link for 2 for $10 (give the other one to your spouse/parent/kid/someone): https://www.amazon.com/dp/B01CQN0DDC/
Either place will find the tool potentially flying thru the cabin upon an accident. Strap it down. Same goes for fire extinguishers, jacks, and tools kept in the cabin. If your escape tool knovks you unconscious in the wreck, it does you no good.
Mine has velcro to keep it in place. Will it work in a roll-over? No idea, but yeah, definitely need it to be with in hand's reach for it to be effective.
After a roll-over, it won't be there and you may not be able to reach the glove box. If you have a center console, I recommend keeping it there (that's where I keep mine).
If you're reading this and you don't have one in your car, buy one now. Here is a link for 2 for $10 (give the other one to your spouse/parent/kid/someone): https://www.amazon.com/dp/B01CQN0DDC/