After Thaviks disappear and goes invisible after taking damage, it is possible to see him climbing the walls on the arena. If you shoot him, he will fall off and instantly die, ending the strike
Video proof: https://youtu.be/eCRjzlDBuCY
I assume this is a cheese.
[spoiler]Video not mine[/spoiler]
-
This nightfall, like all the others is actually really easy with a bit of coordination. It's just frustrating that they put timers on the content to add some artificial difficulty. This is made worse by the fact that the nightfall (and i do mean all of them) are designed to slow your progress by making the boss run away or making him invulnerable for a period of time so of course people are going to use a cheese if they can. The timer has really sapped the fun factor out of the nightfall for me. Even though we can still do it i'd much prefer to take my time and slaughter everything than be forced to run past large groups of enemies for the sake of time.