Hard to give a shit when you have to take one

The unignorable barely containable urge to take a crap.

For example: You and your mother hurriedly crossing a busy street to the nearest bathroom when she suddenly falls down as you see a bus in the distance quickly closing the gap between it and her. You scream an apology without missing a step asking the other pedestrians to please help her in lue of you trying to save her and shitting your pants in the middle of the road.

For example: You and your mother are hurriedly crossing a busy street to the nearest bathroom when she suddenly falls down and in the same instant see a bus in the distance quickly closing the gap between it and her. You scream an apology without missing a step asking the other pedestrians to please help her (in lue of you trying to save her and shitting your pants in the middle of the road). This would be a case of it being hard to give a shit when you have to take one.