Think/Tick are expensive time constraints in Gmod for any code.
I'd look more into possible equip/select/deploy hooks before using a think every tick/frame.
It's been years since I tinkered, but poking into the wiki, tool:deploy might be a better hook.
http://wiki.garrysmod.com/page/TOOL/DeployBe warned though - even if you develop working code, exploits/cheaters will abuse this.
Imagine how easy it will be to switch from a weapon/pvp to a tool/god just to avoid being killed.