Iron Banner Eruption Mode. How does it work?

I am free to play and cannot find the answers in old YT videos & online guides.

1. in some matches yesterday, i was constantly exploding and just died out of nowhere. I figured out, that there is a timer on the screen. Some guides mentioned the timer will extend as long as you are keep killing enemies. But how on earth can i keep a kill streak without dying or exploding?
2. I have tried several times, before the timer went to 0:00 to kill the enemies with the eruption/explosion. It seems not working and they don't get any damage. So, can the eruption kill the enemies as well?
3. sometimes there is mark on team mates or enemies and you can see their countdown. What am I suppossed to do, when teammate run out of time? How can I protect him? Lord Shaxx (the ingame voice) keep saying "go out for hunt" or something like that. Or Hunt is over..not really understanding what I should do in this moment.
4. Most important questions. I CLEARLY have no countdown/timer. My screen do getting bluring BUT there is no timer. However, I still explode and die. Why? Is this a visual bug that the timer is not always showing? Or I errupt/explode, because i didn't protect my teammate with that red mark?

Reading the ingame description about the game mode is like listening to my 3y old child talking. I dunno understand anything :-)