Hmm... yeah, Rustler/Pest are becoming somewhat tricky cases to explain.
Rustler counts since it's using
![Light :light](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/light18x18.png)
to produce
![Life :life](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/life18x18.png)
- it's using 1 ability to interact with 2 quantum pools at the same time.
Pest doesn't count with the current rules because it's use/drain of quantum isn't in 1 ability -
![Earth :earth](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/earth18x18.png)
Burrow and draining quantum are two different abilities. If it was something like "
![Earth :earth](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/earth18x18.png)
: Burrow and generate
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
.", it could work.
So to summarize, the way I interpreted it, 1 ability has to do something to two elemental quantum pools.