Can you cancel emergency sos even after the timer is up?

Yes. Once the timer is up the phone immediately makes a call to the emergency services, so very quickly tap on the red phone button to cancel the call, as you would with a normal call! But in most countries the emergency services take a dim view of this, and you could be called back to explain what´s going on! This happened to me when I first got an iPhone X and was fiddling with it. I was cautioned not to waste their time. Best to wait until they answer and then apologise, explaining it was a mistake!

If you're worried about this happening go to Settings > Emergency SOS and turn everything off! Hope this helps you! Regards, Ian.

Just go to Settings > Emergency SOS and make sure the two sliders ("Call with Side Buttons" and "Auto Call") are not showing green, which is "ON". Slide both to the left until white is shown. Emergency SOS is now off. You can still get to it in an emergency by holding down the Volume UP button and the Side Button at the same time and then waiting for the display to appear with 4 options, the 3rd of which is Emergency SOS. That's it! Regards, Ian.

Sorry, I really don't know, but I imagine it would do if Auto Call is turned on! As I understand things this is to allow you to make a quick call when the phone is in your pocket and you're in trouble or otherwise disabled!!? But since my brush with the emergency services where I live I've turned SOS off, as I mentioned! 😊 Maybe someone else here in this forum can help you here! Or you could look in YouTube, there are quite a few films about Emergency SOS. Good luck! Ian.