How stable is a charged shell on the edge of collapse?

Thin shells — layers of matter hovering near their own event horizon — let physicists test both mechanical and thermodynamic stability in the same system. This study examines such a shell in a theory where electromagnetism is modified at high field strengths (Born-Infeld), finding that despite the shell having nonzero pressure, its entropy depends only on the gravitational radius, not the pressure. Stability ultimately boils down to a single inequality governing how charge flows across the shell.