There is an "intermodule umbilical" that is "shed" at module separation.
In preparation for the split of the modules, external cable lines
connecting the three main sections of the spacecraft and the six
petals of the thermal protection layers on the Descent Module, SA, are
shed. The Habitation Module is then depressurized, while the ...
I'm late, but nevertheless.
I am sure the seats are custom-made mostly for land contact, not atmospheric reentry. The accelerations are far beyond 10 g in that moment, although brief. Some astronauts compared Soyuz land contact with a "car crash".
Solid-fuel rockets soften this at last moment, but not so much. Also in early Soyuz flights there were ...