In a previous post, I used the following command request system configuration rescue save to set the current active configuration as the rescue configuration. Since I have had to use this command to clear the Alarm light that I encountered, I took the opportunity to do a little further reading on this command. If you want to active the rescue configuration, you will enter rollback rescue, followed by the commit command.
Should you want to delete the rescue configuration, which is probably not a good idea, you would use request system configuration rescue delete. At that point, I would anticipate the Alarm light turning back on for the same reason that it came on the first time that I saw it. Since you can rollback to several different versions, I can see using the rescue rollback being used for a base configuration where you can reach the router on the network with some basic functionality but not everything that you would normally use for a normal config.