Full Scan in Safe Mode

My understanding is that the most comprehensive security scan is to scan in safe mode with administrative privileges. I also understand that in safe mode, the firewall is turned off.   And with NS, you have to have "safe mode with networking" in order to do a proper full scan.

If I am understanding everything correctly (and please correct me if I am wrong), is it safe to do a full scan in "safe mode with networking" (which, according to my understanding, turns off the firewall) under an administrative privilege and if not, how do you do the most comprehensive scan? 

I am using Windows 7, 64 computer.