Hello,
Symantec Management Client service would not be running in the Safe Mode, however, you will still be able to scan the machine.
All your Answers are provided in the Article below:
1) Error: "It appears that the Symantec Management Client service is not running." when launching Symantec Endpoint Protection client in Safe Mode.
http://www.symantec.com/business/support/index?page=content&id=TECH105746
2) How to perform a full virus scan while in safe mode with command prompt
http://www.symantec.com/business/support/index?page=content&id=TECH106310
3) Error 0x8007043c when trying to start the Symantec Endpoint Protection user interface in safe mode
http://www.symantec.com/business/support/index?page=content&id=TECH103080&locale=en_US