I think "assigned to" is a good alternative to "came to".
The second part uses an old-fashioned word order, but the tense doesn't need to be changed. Although the word "spank" is still widely used, corporal punishment isn't. You could leave "spank" in there and everyone would understand it, although some of the less innocent might be reminded of certain sexual practices. For an alternative, I'd suggest "punish" as a good neutral word.
I'm not certain what a dressing-room might be. It could be what we used to call a "cloakroom", where students hung their coats (but the word is now used as a euphemism for the toilets), but I think it might be where the students change into and out of their sports kits -- in which case we call them the "changing rooms".