Long story: Simon and Cass ran into some slavers, namely the ones Remmy and his crew of Sentinels had been following. Remmy had been the inside man, who would often been sent out ahead to either lure in the unexpected victims or check places out for setting up camps. In the latter, he and Kurtis would end up sneaking out any unseen travelers before the slavers got there. In this case, only Cass was saved while Simon was caught. It gave Remmy a guilt trip from hell over it and he was determined to make it up to Simon, even blowing his cover to the man and risk his mission. Needless to say things went down hill from there. 

As for Abbie, well she's more a flight then fight sort until you corner her. That's for sure. Only reason Abbie had tried to take on a Blader was because it was trying to kill Lacy and Abbie had to protect her. Angela send a machet through it's under jaw and killed the sucker while Abbie crumbled in total exhaustion.