If the loop animation is set up to loop, simply play the start animation (waiting for it to finish), play the loop and create a loop in your event to while the input is still valid (Wait For Input node). Once the input is no longer valid, play the end animation.
The Wait For Input node's Success slot would connect to a Wait node (e.g. waiting 0 seconds to check again in the next frame), which connects back to the Wait For Input node.
The node's Failed slot will continue to playing the end animation.
Since areas in your scene are set up via triggers, just add an Event Interaction with Trigger Enter start type to play your event when entering the area.