Tapas will allow most things and are mainly limited by appstore's demands in what they do have to forbid. Since your scene is violent rather than sexual there's a 99% chance it will pass by just fine.
App stores limits are heavily based upon america's extremely negative attitude towards sexuality and nudity in its realistic forms (i say this because in a more exploitative fashion, america seems to celebrate it. Go figure.)
So all in all: most violent things that arent hate speech or trying to motivate illegal acts will be fine as long as the heavy stuff is kept behind a mature content warning.
As for nudity, anything above the waist will go fine without a mature content tag (as far as i have understood it at least), anything non sexually displayed below the waist will go fine behind a mature content tag.
Penetration of any kind, erections, and lubricated holes in the netherregions need to be censored even behind a mature content tag. Same goes for ejaculation.