Love at first sight, that's what he would call this attraction to Synthia. It was simple, he was out with one of his friends, and then he ran into her. To make a long story short, the love hit him...and then she did. Felix's behavior varies around Synthia, because although he does love her, he also has a small fear of her as well, knowing that she could easily shoot him dead at any moment. Felix will most likely do anything for Synthia, no matter how ridiculous and dangerous the task may be. Synthia is often the only one who is able to bring out the more defensive side in Felix.
When Felix bumped into her at the club, she reacted instinctively, she knocked him down and aimed a gun to his head. Of course, she soon got used to Felix being nearby wherever she went. It was pretty handy, because she knew that Felix would do anything for her, although, she wasn't sure why...Synthia seems oblivious to Felix's affections for her, and she also seems to not feel the same way. But, she has hinted at times that she may share the same feelings, but has never come outright and said it. Deep down, she really is in love with Felix, she simply doesn't realize it, yet.