How can I squat safely without a spotter (or power cage or rack with adjustable pins) My gym doesn't have a power cage or a rack with adjustable pins. It's hard to find people willing/able to spot. Any advice? 

Note: the rack's built in, non-adjustable safety bar is significantly below the bottom of my squat, to the point where I don't know how to bail out safely. This problem is significantly holding me back because I don't feel confident consistently adding weight without having a cage with adjustable pins. 