No, there are no event subscriptions in Rule Machine except for what you define as triggers. (That's actually a bit of a lie since there are effectively subscriptions or schedules created for certain rule actions like "Wait for...," but I'm talking about things that force your rule actions to run anew. Conditionals in RM do not create subscriptions; you need triggers, which in RM are explicitly defined.)
If you haven't read the Rule 4.0 docs yet, I'd suggest taking a look. (There is a bit about Rule Machine history in there and some assumption you knew Rule 3.0, but you can ignore the history lesson and just see how things work in the current version.)