Error : lua/scp294/sh_method.lua:237: Tried to use a NULL entity!

```lua
Error : lua/scp294/sh_method.lua:237: Tried to use a NULL entity!
  [C]:-1 - TakeDamage()
    lua/scp294/sh_method.lua:237 - func()
      lua/scp294/sv_hooks.lua:35 - v()
        lua/includes/modules/hook.lua:96 - ()

```