What happens if you try to do two triggers at once ?
For example when the monster appears in the storage, you run down the stairs and open the door in the kitchen while the other monster is still chasing you?
You can have as many monsters as you wish and trigger them whenever you wish.
PHP Code:
SetEntityActive("<monster_name>", true);
You can spawn as many as you would like with this, you just need to figure out when it is necessary to spawn them, which you will define in scripts with CollideCallbacks, InteractCallbacks, Timers, etc.
should work just fine as long as you have 2 monsters. If you do 2 triggers on the same monster, it's possible to reassign pathnodes or teleport the monster, among other things, all depending on what you want to do.
If you are referring to actual storymode content, the gatherer which patrols after you find the elevator rods in the storage, then I think that is supposed to resemble the same gatherer which resided behind the closed door by the kitchen, deciding to take a stroll. The door might also be open after this event, even if you did not open it yourself, but my memory is vague as I have not played the game for a long while. ;)
When it comes to running from one monster spawn location to another monster spawn location, I do not think this will be easy to do in storymode. Of course, I may be wrong, but the last time I tried to do something like it, I failed.
If you mean in technical terms, like making custom stories etc. then I would imagine doing two triggers at once should be no problem, though I do not know for sure how the technical things of the game works.