Yeah the terms are all accurate but it would regardless be insanely dumb to climb an uncleaned wall like that in that situation.
which is fine, it's a dumb manga, just kind of annoying when they try to mix realistic with absurd like that. doing a hand jam and then swimming back in the ocean would be a very easy way to get a fatal infection. Just tons of ways to cut yourself or injure yourself rock climbing with wet hands on wet rocks and even if it's overhanging yeah.