Funny thing about my dad. We were watching some war movie and the solders were going house to house kicking in doors and running in. He laughed at that. Before his squad went into a house the first thing they would do is use frag grenades, tommy guns and grease guns and reduce the door to splinters. There wouldn’t be a door there anymore. Then the next thing was either smoke and/or frag grenades went in. Only after that did someone go in through a window with a 1911 and never through the door - only if there were no other choice of entrance.
Another life lesson your dad may have mentioned is when you hit someone, put three more into him to make sure he stays down. Saves problems later.