If the dolphin’s residence was left open to the sea, then the dolphins themselves could decide where they wanted to live.
No doubt, some dolphins would decide that it is far more interesting, challenging, exciting, and secure to stay in the residence and perform.
They are supposed to be very intelligent mammals, so you would think they must get bored silly living in the ocean all the time.
Do our cats and dogs run away whenever they get the chance because they are overwhelmed with a passion to live the wild, independent, life? No,
So why would the far more intelligent dolphins want to?
Anyway, if they were free to choose, it would end all the carping about locking them up and weeping over their loss of liberty.
Perhaps the performances would have to be more dynamic if some of the performers decided to take a short vacation to the sea.
But that could be mitigated by training more performers.
Or perhaps the exit gates could be opened after the last show of the day.
Then the next day’s show could be arranged around those dolphins who decided to stay for the night.