Cassandra keeps on telling me to disrupt the rift, and the on-screen directions show that I need to do a right-click. But where do I need to be standing to do that? Looking up, I can see the "DISRUPT RIFT" label, but right-clicking and/or F don't seem to trigger the rift disruption. I feel like I'm missing something obvious, like having to be at the same altitude as the rift or something like that.
Here is how it works, the option of disrupting the rift is NOT always available, only at specific times. Here is how it pretty much goes:
1) You approach the rift close enough, the first wave spawns.
2) As your companions fight this wave, you approach the rift exactly the same way how you will do it if you were trying to close it, but instead of closing it you should see the option of disrupting it. It is exactly the same icon. It is tricky to do it because any attack from any of the demons during the cast will break your attempt and the cast of the spell takes a while, it is highly likely that you would be interrupted unless you guarantee that your companions have the attention of ALL the demons in the wave.
3) Once you and your team kill the first wave, a second wave spawns. Be aware that during this spawning phase, the option of interrupting the rift is NOT available.
4) The second wave spawns, and again, while your team is fighting the demons of this wave, you approach the rift and try to disrupt it, again, any damage received, regardless of how mild it is, interrupts the attempt and you need to start casting again from the beginning.