If you're so tired that you collapse to the ground, walking up a flight of stairs to get to sit on benches is not good suggestion. It didn't seem like they were carried up those stairs either.
Did anyone else notice that on page 18, they named themselves incorrectly? From the 3rd panel, we can see that Meiry is on his right and Yuufi is on his left (Due to the hair part). Except, in the 4th panel, the text tries to insinuate that the one on the right is Yuufi while the left one is Meiry. Not sure if the author/translator themselves got it mixed up or if it's supposed to be the result of them being so exhausted.