I carry a resqme, too (it's been on my keychain since it came out and was tested favorably), but you'll want to remember that the Ascent's front and second row door glass are laminated. This means that the resqme will have very limited, if not little-to-no, effect on this glass.
IIRC the pano moonroof is also laminated, but the standard moonroof has tempered glass (not that this will do any good if the vehicle is inverted in a roll-over). The final option is through the glass in the third row, which is tempered.
If you live in a wet area (river, lake, etc.) in-particular, be sure you have a backup plan.
Also, note that you'll really want to have this item securely mounted - kathythn, the cupholder is a great place for this tool, as it keeps it very handy, but in a collision, the cup that you've place the tool in may itself displace. Be sure that the tool is not only handy and easily retrievable by its intended users, but also that it will remain at its station/staged access point even in the chaos of a collision or other event.
Finally, for anything that is spring loaded, consider also a manual backup. With the resqme specifically, there have been folks who report of either its complete or partial failure during testing - with either a complete failure of the spring mechanism to properly actuate or a failure of the initial or a following strike, with only furhter subsequent deployments being successful.
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And I know that this is a bit off-topic, but if you carry one of these devices, please take the time to actually get in a bit of practice with it (and this extends to your loved ones as well). The seat-belt cutters work easiest at a certain angle, and this is not something that you'd want to be playing with when under-duress. Similarly, even for vehicles with tempered side windows, users of these devices need to understand how the punch - even ones like the resqme, which do not take much/any strength to deploy - may still cause the user's hand to "push through" the window, and how this may cause some cuts, as well as realize that even when the tempered glass shatters, often there will be sections that will hold together and may need to be cleared out of the way prior to a safe/efficient exit.
These items are not totems or amulets - just having them doesn't mean that you'll be safe. Be sure you know how to use them properly, before the need arises.
Finally, remember that in a roll-over scenario (whether the vehicle is completely inverted or on its side), your weight will be shifted differently versus what you'd normally expect. Before cutting yourself loose from your seat-belts, take a moment to brace-up against something substantial so that you won't "flop" out of your belted position, which may cause [further] injury.