He's reliving trauma over and over. A subconscious attempt at resolution via catharsis. Always failing. He should take shrooms prior to his next patrol. Probably achieve some kind of breakthrough. Get together with scarecrow.
Meditation, in a nutshell, is about manipulating and cultivating your attention (the buddhists call it "awareness"). Step 1 is finding a meditation technique that works for you. Experimentation may be necessary.
Here's my favorite meditation guide. It's short, clear and has nice pictures.
Why do you hate sensuality?