If you tell us what you want to do, we may be able to offer you a solution. Have you looked at pleg plug in? Vera will kill anything that takes longer than 60 to complete. Scenes are meant to run their tasks and complete in a short time.
i looked at PLEG and yes, it is an every good plug in for vera. however, i try to do with lua code.
what i try to do is writing a closing scene for garage door. the scene would be triggered when garage door is open (door sensor is tripped). it would check for sensors in garage door and if no motion is detected for period of time and garage door has been opened for period of time then vera would issue close to garage door. during closing, if motion is detected by sensors. then action would be canceled and start all over again until garage door closed
You can not do what you want via luup in a scene. Long running tasks will be killed if they run longer than 60 seconds. If you are set on running it via a scene, you can create a scene to run at an interval and have it check the status of the sensor and perform your action.