It's also possible that the root shell is opened up when the tamper seal is triggered.
Ie. The system is either in secure mode (with all necessary crypto keys for operation), or it is in insecure mode with a root shell open for debugging and failure analysis, but that transition also deleted the critical private keys.
Ie. The system is either in secure mode (with all necessary crypto keys for operation), or it is in insecure mode with a root shell open for debugging and failure analysis, but that transition also deleted the critical private keys.