[ravenfish]

I probably wouldn't spend too much effort on rules for closing eyes against blood agents. While the membranes of the eye are one entry point, there's also the mucous membranes of the nasal passages, which are harder to quickly- and even considering only the eyes, closing them doesn't create anything like an airtight seal. Ultimately, if you want anything more than a small bonus to the resistance roll, you'll need a sealed face mask.