If the choice, we needed to make fit into something we would want as a universal law then it would be considered a categorical imperative. The categorical imperative could be compared to what Jesus says to us when he says” Do unto others as you would have them do unto you”. Kant just wants us to stop and think before we react to a situation and wonder if it was something we would want for everyone to do.
In the question asked above asking whether it would be morally acceptable to torture the victim I believe the answer Kant would give is no it is not acceptable. Kant would argue that torture the suspect isn’t something he would want done to himself nor everyone doing to each