Gliders can open the slide up feeder doors on most cages.
I think the Prevue Flight cage has a light weight bottom grate which would not take much for a glider to slide out just enough to get into the cage pan then slip out of the cage between the grate and cage pan.
You can zip tie the grate and all of the slide up doors to secure them.
Check around the cage as well to see if there are any spaces that are slightly wider than 1/2 inch. With the light weight cages sometimes the bars closest to the edges of the cage are slightly farther apart where the two sides meet. Check all around the cage where the wire meets the frame to see if there is a space you can easily slip your entire finger or thumb through.
Gliders are smart - if they found ONE spot that is wide enough to use to escape they will go back to it every time they want to go out for an explore.