i can see dr breen and cave johnson going to a fancy charity event (representing both of their companies) and dr breen says something that pisses cave off enough to make him vault over a table to tackle him. their outfits and the white table cloth get stained red from the bowl of punch cave knocks over in the process and an image of cave johnson beating the shit out of dr wallace breen is on the front page of every newspaper the next day

i know cave johnson was already old and dying from moon rock poisoning in the very early 80s and dr breen was around and in charge of black mesa in the 2000s but forget that for a second. OR imagine old man cave beating young breen up with his walker. your choice