Gun = Rootie Tootie Point and Shootie

Actually this is Akira Kurosawa's Ikiru from 1952, an equally great film (and that's saying a lot)

Source: I downloaded the subtitles, this scene is around the 2 hour 6 minute mark

Streetview location for anyone curious: https://www.google.com/maps/@51.4999334,-0.160752,3a,75y,87.44h,88.49t/data=!3m6!1e1!3m4!1sDwcEBHkHn_jY82XL974nPg!2e0!7i16384!8i8192?entry=ttu