I recently attended an SD course at my gym, hosted by Kru Bob Spour (look him up, he's a top guy!). While I've been doing Muay Thai for years, the things we were doing were in realistic scenarios and the emphasis was on speed and reactions. In close quarters (ie a busy bar or crowded area) the first thing we were shown was a palm heel strike to the head. It is SO simple and effective, instant KO if you apply it with purpose. In these situations you would not want to punch as there is a huge risk of broken knuckles, wrist injury etc. Elbows were the next subject, excellent weapons and if you train muay thai you'll have a good idea of how to apply them. Knees are also effective but only to bring the attackers head down for you to land a head strike. Kicking is out. Firstly, chances are you'll be wearing shoes which are not appropriate for a thai kick or even theep; secondly, you are likely to loose your balance on uneven ground or if wearing high heels. Also, you wanna keep your feet below you in case you have more than one attacker or want to run away. I could write loads more bout it but don't want to bore you! Thats the first time I've done a specific SD class as I always thought I'd be ok with my muay thai; Bob showed me that sometimes, its not enough.... Best advice is to stay switched on and if something is starting, get outta the way if you can.