This would be good. Takes 15 min to code this in and you dont have to go redesign a bunch of stuff like some on here are suggesting. Obviously they dont care what it looks like. Fine. But safeguard for such a monumental action they should have had.

I've interacted with systems like that before. My brain looks for the quotes, I double-click to select the text, Control-c, Control-v, and it's done... completely on autopilot.

Trust me, if you get in your users way they will find some way to get rid of you.

this would probably be a bad design aswell. because if a real missle treat happens I would need to get out the warning as fast as possible. the best way would've been a second page with a big button and huge warnings.

You were modded down, but I agree. Contrary to popular opinion, "duck and cover" is not just psychological pacification. It will save lives if worst comes to worst. Literally every millisecond counts when issuing a warning of this nature.

So, yes, bring up a huge flashing red warning dialog with a single confirmation step. And make it easy to issue a retraction.