If SEB really cannot be quit, you need to force restart or force shutdown your computer.
SEB is free software, we provide it for free without any warranties. We understand you may be under pressure and stress, so are we often. No, you have to directly contact the vendor of that custom SEB version or application based on SEB. I'm using a custom version of SEB (which is called differently, like SEB or another application name, but I know it is based on SEB) and I have a problem, can you help me?.
If no quit password was set up, try to just press the enter key. We don't know the Quit password which is used for your exam and we cannot find it out. There is no default SEB Quit password, it is always set up by the people who set up the exam. Then you need to contact the exam support (your exam organizers, teacher, proctors, etc.), because they know that password. Sometimes SEB displays a red lock screen, when something happens during the exam, which would make the exam insecure. If correctly set up, after submitting an exam, the exam/learning management system displays a button or link to unlock the device and quit SEB/the exam session without having to enter a SEB Quit password.
We only develop the SEB application itself (which is basically a special, kiosk/lockdown web browser).
SEB can be used with numerous exam systems, learning management systems or other web-based e-assessment systems. We don't know the Quit password which is used for your exam and we cannot find it out.). They know the exam and the exam system they use, they hopefully set up and tested everything properly, they have configured the settings for SEB for that exam, for example the SEB Quit/Unlock password (there is no default SEB Quit password, it is always set up by the people who set up the exam. Always first contact your exam organizers (the people or organization which let you take that exam).