im 100% okay with the Martha scene
pretty much every film we watch has coincidences. some far far less believable and dumber than their moms having the same name
batman was in a bloodlust. kicking superman ass and he was about to have a kryptonite spear rammed through his body. SO what will boycott superman last thoughts be? save his mom. it humanized superman to batman and takes him out of his bloodlust.
totally believable and half as ridiculous as the coincidences and twists thrown in marvel movies that motivate characters.
I know im in the minority though.