Hi /u/AdiSoldier245!

I think the best way to understand, why photons cannot escape from within the event horizon, is the following way:

According to General Relativity, gravity is the curvature of spacetime. The stronger the gravitational field, the more extreme is the curvature of spacetime. Inside the event horizon of black holes, the curvature of spacetime is so extreme, that no path through spacetime exist for photons, which lead anywhere else but to the singularity at the center. That is, spacetime itself is curved so much, that there is, physically and geometrically, simply no path that light can follow to the outside.