Spook somebody armed with a real sword, yeah what a smart idea for a prank, Jin. With how slow things are going, this chapter could pass off as an ending for some axed manga out there. Not this one, though. The slow life is the point here, this is supposed to be a comfy read (although I do admit I want a bit more speedup on the romance side).
On the flip side, author is trying way too hard to make Sera look cute, which just backfires for some people and makes her look silly at times. She's already naturally cute anyway, we could do with less oohs and aahs from her on seeing any more mundane tools from Earth.