@PKirkby
Yes, I can.
There are a lot of ways doing that, including the script call.
But since you ask that question, and don't know how to achieve that, I first recommend you to do this with the event command tabs, so you can know a little more about the engine
So, going in that way, you ask:
Just to explain the screenshot that I gave to you before:
Go to control variables > Choose a variable to store the position X of the event > In OPERAND, choose Game Data > Click in the tab Character and choose the event you want to check > in the right side, choose Map X.
Repeat the same process to store the event position Y.
So now, you can use the conditional branch to check the variables that you used(Which would be the positions X and Y of the event) with the coordinates that you want.
Alternatively, you can set the variables to store the position of "this event", in case you want to put this check in the event itself.
With that, you can check the coordinates of the event.
However, with script calls, there is a way to do that, that I think it's best to event everything:
You can put that in a parallel event.
var rock = [put here all the event id numbers that you want to check]
if($gameMap.event(eventId).pos(X, Y)) { // replace the X and Y for the coordinates you want to check.
If an event is in that specified position, it will be erased.
OBS: you can put a wait command after the script call to avoid lag. I think if you put 3-5 frames it would be nice.
I hope it helps!