Security issue if I restart TMG services?

Hi

I faced high cpu problem on one of our TMG servers and it was caused by Windows Firewall service. After investigating I thought to restart the service and when you are going to restart it, it asks you: Do you want to restart these related services too (many TMG services). At this point I started to wonder what will happen if I restart TMG services. Is it a security risk? In worst case scenario there is network attack going on and if I restart all the services will it allow connections come through while TMG is restarting?