You can leave your luggage at a seat in the lounge and leave the airport. Although it is unlikely to have your bags taken, I would not leave anything of high value in them. I travel alone and have often left my bags unattended in United clubs to get real food and never had a problem. Keep in mind everything is on camera so if something happened you at least have some evidence available.
To go to in n out you can easily walk depending on the weather and your physical fitness. Just study a map to find the walking paths from T7 to T 1.