It looks like the opponent destroyed your void anchor at the exact moment they got marked (or they were simply too quick to be fully tethered). It’s a slight oddity, but it was not a surprise to me that you died in that situation (I’ve mained Deadfall since TTK). Tether has always had a delay on it that prevents it being a helpful “panic” super. If you want to use it in that kind of situation, you need to land it much closer to yourself (to stop your opponent whizzing through/past it) and somewhere they won’t easily destroy it (eg ceiling/behind something). It’s pretty hard to do when your opponent is close range and charging at you, so it’s usually best saved for a different situation. Personally, it’s one of my favourite supers. It’s extremely tactical, with high risk/reward.