Not all the jobs are clean and precise. Sometimes you need someone to do a dirty job. Sometimes it takes some rules to be bent or broken to get the job done. Sometimes it takes some people who just don't care about the rules.
Apellen Squad are happy to do that for you.
Apellen Squad hail from Catachan. Most Catachan soldiers already have a healthy disregard for rules that come from high up in a command structure where the person giving the orders is not on the front line (or even on the planet). As such they are happy to do things their own way and get the job done using whatever is to hand and doing whatever it takes.
Their gear is an eclectic mix that takes the best of what is to hand and mixes it up. No standard issue gear here or standard pattern lasguns.