I have taken quick notice of this as well. It would make a lot more sense to keep the pickup items appear, if at all, from the few boxes that appear in the depths before the safe area. They are scarce enough to turn what usually appear commonly at the drop of a hat into highly valuable tools that require extensively crucial and sparing useage to improve survival, making detours to the dead-ends they show up at much more meaningful.

And while you mention it, the toughest, cheapest and laggiest battle would go to the last room in Grinchlin Assault. There is as of yet no alternative or no exception to this case, its difficulty and design are truly the most unforgiving in the game.

@Bopp: We would all be happier if every one of the boxes in the safe area dropped only Crowns, Heat and Rarities (and maybe even weapons and gears, if the dropchart tables still allow it nowadays) without going through with substracting their amount. Even this suggestion as well as the aforemented recommendation are more than reasonable enough to push for.