I will be (the lone, so far?) voice of dissent on the Samsung buttons. For a "Reliable in a panic" situation, I would have no faith in them. --And it's not about the strength of the mesh. It's about the fact that, after a period of inactivity, I believe they sleep. So, if you leave it alone as a panic button, it's likely going to use your first button press to wake it up. I would find that unacceptable.
There's a little delay once they wake up, before they've found their place on the mesh and start receiving commands. Those who have no problems with "first click" on these probably use them frequently. They sleep for battery protection, so just keep that in mind.
I agree with the others that "truly reliable" is going to be going with something hard wired and/or UL listed, which means underwriters have certified something for you to trust with your family's life.
As for general stuff I have lying around that I'd trust over a Samsung button (of which I have a couple, and use them--they're fine, not knocking them in general), I'd trust a Lutron pico through a Smartbridge Pro. Picos communicate through a much simpler RF to the hub, consume basically no power on standby (and thus don't need to sleep or stay awake to stay "on the mesh," and then they send a signal to the Smartbridge, that signal is sent to the Hubitat hub via telnet. SO no issues about "Strength and reliability of your mesh," etc. Of course, none of this will work unless your networking switch, Smartbridge Pro, and Hubitat have power. This is where, once again, a UL listed security system shines, as they are required to have backup power. Of course, there are UPSes available.
Good luck with whatever you're trying to achieve! But I would not personally go with a Samsung button for "first click in a month" reliability. Not by a long shot. Even when I was on SmartThings, I was annoyed at how unreliable they were from sleep. These days, I usually use them as triggers for RM4 things I'm testing.
just my $.02