For what it's worth and based on my own interpretation of his actions, my experiences and attitudes...
I would plump for one of my original theories of an affair with an American Serviceman's wife who possibly works locally in a pub, club (or not) and has access to a car. He's been seeing her on and off and when he can. She's stuck in a US base with limited interaction and needs a buzz. Corrie is that buzz. They met on neutral soil originally (night out/weekend social function on US base?) He's been sending her messages after leaving the club to meet her whilst her husband is away. The husband has intercepted the phone and messages, gone to meet him, hard punched him into the back of the car, phone fallen out of shirt pocket, phone goes into the bin and Corrie is driven away.
Its right that we've discussed Corrie having possible involvement with Tinder AND Grinder AND drugs AND awol AND....that is what this forum is designed to do. To address difficult topics with a view to finding a near perfect answer to a problem. As unsavoury as they are, we HAVE to discuss them to solve issues.
The last theory of mine is that he was a secret Harry Potter fan and he'd just found Platform 9 3/4!!