A more thorough explanation:

Term: in alio loco
Definition: In another person's position or place.
Example: If I were in alio loco, I would have made a different decision.
Explanation: This means that if someone else were in charge or in the same situation, they would have acted differently. The example shows that the speaker is acknowledging that their decision may not have been the best one, but if someone else were in their position, they may have made a different choice.