Understanding "Between" or "In Between"
Hello, and thank you for the great question!
'In between' and 'between' can be used interchangeably when talking about being between two physical points or locations or between two events or times. Therefore, in the example you mentioned, you could use either 'in between' or 'between'.
However, 'between' is the better option in formal writing, and there are some instances when you can't use 'in between', such as for oppositions and comparisons, for numerical, time or age ranges, or when you are speaking about sharing or dividing.
Therefore, the safe option is to always use 'between' because it works in every situation.
I hope that this explanation helps you.