This move was an innacuracy. But why?

So i can kind of answer my own question, the engine figures theres more to be had if they did it this way.

The scenario is this, there was a hanging piece which a queen could take for free, but instead the game review retreated the queen. My question i suppose is when the show moves only shows the one move which i would never would have done ina  million years, how can i find out WHY they moved the way they did and what was so wrong with the move i would of played instead? 

Look at the lines the engine gives.
Otherwise post the position here.

im pretty new how would i post the position but it doesnt matter it was a low stakes move anyway just didnt understand why the take wasnt on.

if anyone can answer what i should have done, or does the engine have my choice in it anyway?