If I'm cornered by a crazy man who's shouting and dousing me - if it hits me in the face, quite literally inoculating me - with God knows what? Even here in duty-to-retreat Baltimore, you'd have a hard time calling that other than self-defense.

Not relevant to the parent comment but in places like the UK where acid attacks aren't uncommon, that can be a concern.

Acid attacks are incredibly uncommon in the UK

For anyone curious about the rate, these articles https://www.usatoday.com/story/news/world/2017/04/27/acid-at... https://www.vice.com/en_au/article/z4dy43/why-acid-attacks-h... http://www.dailymail.co.uk/news/article-4462016/Two-acid-att... suggest that (on average) there is more than one attack per day in London alone.