There probably will be questions about past alcohol or drug use in your packet, if there is be sure to mention it. Any omission of information about your past could be a deal breaker.
The issue of a specialization probably would be okay, but it may seem that you don't really want to do any of the grunt work first. Two years is a very short time to be moved into a unit like that.
Good luck.
Job Security...
Ecclesiastes 8:11...
Because sentence against an evil work is not executed speedily, therefore the heart of the sons of men is fully set in them to do evil.