The video shows a man transporting a fish from a bucket of nice fish-friendly water to a container filled with an unspecified substance (we know it's not liquid nitrogen, as the temperature is shown at -35 in the beginning, which is too warm for nitrogen to still be in liquid form, no matter the unit).
A subduction zone is formed at a convergent plate boundary when one or both of the tectonic plates is composed of oceanic crust. The denser plate, made of oceanic crust, is subducted underneath the less dense plate, which can be either continental or oceanic crust.
Identify each type of convergent plate boundary. Since oceanic plates are denser than the continental plates, they will subduct to great depths when they converge with continental plates. When two oceanic plates converge, the denser of the two will subduct; whereas when two continental plates converge, neither will subduct. Therefore, the resulting geologic feature depends on the types of plates that converge. Depending on the type of plate convergence, different features could result.