Why would you have to hide it? You have contract with your employer and it is normal to sometimes look for better contract elsewhere. Sometimes employer might use unfair means to keep employees but is that the kind of workplace you want to work in? I would be open about it and from it's reasons. Sometimes they might even make an counteroffer or change things to better. At least this is how it should work in adult wor…
Not in the US--it's pretty rare for a full time employee to have some kind of contract that retains their employment. In fact in a lot of states employment is considered 'at will' and you can be let go at any time for any reason (or no reason!). The big exception is if you're a 'protected class' like certain races, above a certain age, etc. but that just means the employer has to prove they didn't fire you because of…
"Certain races" are not a protected class. Race itself is a protected class in that you cannot be let go for reasons of race.
Of course, as you already said, that really doesn't matter. If they want you out, they'll find a way.