So just one letter changes the meaning from entrance to exit, that's easy, both to learn and to mix up lol (at least the written versions) вход vs выход
It's actually the different prefixes for the root "ход" (motion, passage, progress). "в" describes moving inside (from outside) and "вы" - vice versa accordingly.
Oh come on. You act like this danger isn't everywhere.
I'm reminded of a game I played once with a mix of native English and native Spanish speakers. One of the native English speakers tried to say they had a huge amount of points (I'm sure you already see where this is going)
He dropped the "n" in "puntos" when he said "una montaña de puntos"
So, so many laughs.
Indeed: in my teens I practised my English, as it was getting rusty, by giving tours, and one day I said b¡+ch instead of Beach. lol. Imagine that in front of 40 unforgiving tourists that laughed from me the whole tour