What did Mary Chapin Carpenter mean when she said, "I found my lifeline at the grocery store"?

i decided to stay late in the laboratory to continue my experiment with the lightbulb. at midnight, thomas edison opened the door and saw all the stuff he was working on. the lightbulb, film and the transmitter. as he walks in an idea hits him on how the lightbulb would work. he would have to change a few wires around to get it to light up. when he did change the wires around it worked so he decided to write a telegraph to his friend to tell him about his success.   as he was packing up he grabbed the telegraph and walked to his home. he told his wife about the success and the next morning mailed the telegraph.

in the line from the end of the story "the cask of the amontillado," by edgar allan poe, the narrator has put the last stone on the wall, thus sentencing fortunato to death. just like that montresor associates his feeling of sickness to the humidity of the catacombs, and seems to be glad he has taken revenge on fortunato. however, montresor's last words are "in pace requiescat," which mean "may he rest in peace." as a result, it can be inferred that he hides or does not want to assume his guilt or remorse for killing fortunato in such a horrible way.