[TOMT][Anime]Scene where old man is just gardening while giant monsters fight

So this old guy is either pulling weeds or watering his melons while there's this climactic battle going on, maybe with giant robots, and a younger dude asks him why. Old guy says something to the effect that his melons need to be tended to, and if he dies, then he'll have died doing what he loves, and if he runs away or hides he might die anyways.