it allows the action to fail implicitly and gives you greater granularity in the randomness of that.

for example, in the shelter downstairs there are 4 spots. 1 is me, 1 is the mob. someone trying to push that mob has a 2 in 9 chance of getting a free locale from this code.

e.g. its getting a 'chance to fail pushing%' adapting to 'available spaces to push into' mechanism for free.  that's to say, the original mechanism fails more, the more crowded a space is. i found that so lovely i went on using it 

differs from setting a manhack free since we need to fail at pushing depending on how much space there it. with the manhack there is space or not. different scenarios.