And if it ever came to that most of us here probably know how the script would go down.

She wasn't doing nothing!

Literally assaulting with an object that can fragment and damage the eyes, or even more importantly cause an allergic reaction.

It was only an egg!

As mentioned above, people are allergic to eggs, so that's strike 1. Strike 2 is what I said in the above comment about eggs being easily emptied and filled with other things, mostly liquids. So that's paint as another comment mentioned, acid/bleach/cleaning products, alcohol [with or without additional fire afterwards], urine/faeces, actual weaponized materials. Hell, just a rotten egg would be applicable.

And in addition to these shitty attempts at defending themselves they leave themselves further open by not considering the allergy aspect, or how a "poorly aimed" throw might hit the eyes. It's part of the entire point around the laws on assault because they can go so wrong so easily.

The human body is a remarkably resilient thing that's also absurdly fragile. A well placed punch to the sternum can stop the heart and kill. People have slipped and hit their head from falling and that's been the end of them [Dr Robert Atkins of "The Atkins Diet" fame for example, slipped on ice, hit head, fell into come, dead week[s?] later]. It doesn't take much to kill which is in part a reason why attention seekers "attempting suicide" are often just that since it's a lot easier to cause sufficient damage to the body than most might realize.