What happens when a plane makes an emergency landing?

"a "single flight diversion" can cost anywhere from $50,000 to over $600,000. The actual figure per diversion will be dependent on the core reason " and "The first is a forced landing, which Netskar described as "an immediate landing, on or off an airport, necessitated by the inability to continue further flight. A typical example is an airplane forced down by engine failure." "

I take this example means the core reason is engine failure, so the $600k isn;t really the cost of diverting.... The engine cost would be the same regardless of the safe landing location.