bingo.
Training to be proficient from the guard is a good thing, but why put yourself there if you don’t have to. I see it as a last resort.
Someone mentioned headbutts. I’m not a fan of them while on your feet, but they are a great way to pass a guard. Very few people train to defend a headbutt from the guard.
Eye jabs or flicks were also mentioned. I think they are one of the most valueable tools in a bad situation and one of the best knife stripping techniques. Not pretty, but effective.