firewall in HyperV

Hi 

I am seeking the following windows server 2012 R2 firewall behavior: when the all the server cores are used 100%, the firewall doesn't get assigned any resources. Thus all traffic is blocked. trafic gets reestablished when the server slows down.

I was planning to use a hyperV VM which doesn't have priority access to compute resources to create this behaviour. 

Am I creating a security vulnerability by using the firewall in this way? I understand I won't have VPN access while the firewall is not running.

Thanks