Sink Hole (2013) on Netflix

Plot summary

A massive sinkhole opens under a town and swallows it, and a school bus carrying students goes down with it, deep below the surface. After the fall, the bus is left hanging on the side of the hole, balanced on a broken pipe, far from the surface. Any sudden movement inside it could tip it into the dark below. The students are left alone, and every adult on board is hurt, so the teenagers must find a way to survive by themselves. The one person who might reach them is a small-town paramedic, who has a tragic past to overcome before any rescue can be attempted.