Yeah, admittedly this is a bit confusing. Since there is a lot of information in this, I'll try to unpack it here for clarity.

Both Guilt and Guile are gravity casters. Casting is a general magic system I use in my Gatekeepers novels that I tried to explain naturally throughout the first book. But just for this story, it's enough to know they have some basic flight and telekinesis powers, as does the guard chasing them. So, they both have the ability to fly, but Guilt isn't as fast as Guile, so she was trying not to slow them down. Her(Guilt) ability to gravity cast is also what allowed her to easily pickpocket the guard while they were right in front of him.

I may revisit this story to try to phrase things better and maybe more explicitly state these things.