What's the in-universe explanation as to why the Imperial officer in A New Hope didn't fire on the escape pod?

At the time of filming the lore probably hadn't been that established in terms of droids and stuff, but in the current day there seems to be no good reason as to why he didn't destroy the pod since droids and other non-living creations are very commonplace. So, is there any explanation as to why he decided not to destroy the pod? via /r/StarWars https://ift.tt/bWHTSXa