Super new here, been following a tutorial and now trying to branch out on my own. I have a blueprint that consists of unlocking a numerical lock. When you unlock it, it destroys itself, but I now need it to destroy another blueprint as well as rotate a static mesh, but I can’t for the life of me figure it out. Please help 
Explain the setup. The other, one is a BP you want to destroy, and the other is the door, perhaps ( but just a mesh )?
I have BP_Lock. When the player puts in the correct code, BP_lock plays an animation and destroys itself as it should. This lock happens to be on top of another static mesh that I had turned into BP_doorchains (because I thought I had to) and I want it to be destroyed as well when BP_Lock is destroyed. And finally, I have a staticmesh called Gate that I want to have rotate open. Individually I can make all these things happen with input, but I was hoping to make them all occur when BP_Lock is destroyed.
I ended up relying on an event tick and calling all classes in the other BP. I grab a boolean from there, and then allow the other BP (a door) to then be interacted with. This doesn’t automate it, but it does feel better. The other BP also does this tick get all actors of class and then destroys itself.
Is this efficient, or a waste of resources since its doing that tick check constantly?
In the lock, just have a reference to the chains BP and the door BP ( yes, make the door a BP ),. Then you can call a custom event inside each BP just before the lock destroys itself.
Make the ChainsBP and DoorBP variables publicly visible, the eye
then, when you have everything in the level, you can just assign these with the eyedropper
I shudder to image how you did this on tick 
The waiting on tick is very bad, the rest is fine
Whenever I try to do this through a reference, I always seem to get “Accessed None” as the result
See my bit ( up there ) about how t assign the reference using the eye dropper tool 