hi yolkgames ,
Your images are quite difficult to read, since your event sheet is full of variables names and other stuff we can't figure out until we know what they are.
Here is my take on it :
I think I understand your "box" object has 2 frames : One frame when it's closed, and 1 frame when it's opened.
Dragging the key will make it disappear and open the box, making the frame number change.
On your event sheet, event number 30, you tell your game to set your box frame to 1, then make its animation play, and then make it stop immediately after. That looks weird to me. If you want it to play, let it play, but if you do not want it to play, then make it stop straight away ?
Also, if you are having trouble with having animation frames, you could isolate each frame in a separate animation, and simply change the animations (containing a single frame only) when you need them. This would suppress the problem you could have with animation stopping/playing, which could be your problem since you are saying your box is "opened and then closed".
Hope this helps.