Soyuz Escape System?

[bigdad84]

I'm designing a Soyuz variant and I am just now getting around to adding an escape tower. My question is if the escape tower ever ends up needing to be used, does it pull just the orbital and re-entry module, leaving the service module? Or does it pull the full spacecraft off the rocket and then separate mid air?

[Kryten]

It pulls off the orbital module, re-entry module and payload fairing as a unit; the service module remains on the LV; the re-entry module then disconnects, and the escape-tower/PF/orbital module stack is pulled away by a small solid motor.

[Free Trader Beowulf]

http://suzymchale.com/ruspace/soyescape.html

the crew ride to orbit in the descent module, so the escape system has to lift both the orbital module and the descent module. The service module is dead weight in an emergency so it's left behind.