In this case it's not about "chance", it's about the fact that the French sentence includes the indirect object, therefore it must be translated so as not to lose meaning.
One of the big dilemmas in translation is where to interpret meaning (if a direct translation doesn't exist, if the direct translation is not something that would commonly be spoken in the new language, etc.) and when to use the direct translation. The general preference is to try and preserve as much meaning as possible and use direct translations wherever possible, and in this case, the direct translation is both grammatical (with regards to English grammar rules) and something that wouldn't be weird to say in English, therefore the indirect object should be included. The main reason why it's specified is because you can look at anything in the mirror that isn't necessarily you, such as if you see someone standing behind you in the mirror or you're looking at yourself but then suddenly you start looking at something that caught your attention in the mirror. It's not as odd as you might think.
It's good you got the gist of the sentence but indirect pronouns shouldn't be ignored.
- Il se regarde dans le miroir. = He looks at himself in the mirror.
- Il les regarde dans le miroir. = He looks at them in the mirror.
- Il te regarde dans le miroir. = He looks at you in the mirror.
These verbs are known as "reflexive" verbs because they require an indirect object which "reflects" the subject pronoun to work correctly. There are some verbs where they have both a reflexive and a regular form (where the reflexive form is when you're doing the action to yourself with no direct object and the regular form is where you're doing the action to the direct object), but I don't know if this is the case with « se réveiller ».
Basically, if the verb is reflexive it means that you don't add the indirect object to the English translation, but in the case of « regarder », since it's not reflexive, the indirect object gets included.
It brought to mind the Irish crom, meaning bent or crooked (as in Crom Cruach) so almost antonymish to what cromulent turns out to actually have been created as.
Or also maybe a portmanteau of crom and crapulent, which could perhaps have had the definition 'bent over due to excessive drinking'.
There are many homophones in the course, some of which have been granted a special filter for the "type what you hear" exercise. This probably is the case here where the original sentence was in the singular and the homophonous plural is accepted as well.
But in translation, the singular "il se regarde" (he watches himself) should not translate to the plural "they watch themselves" (ils se regardent).
"They look at him in the mirror" cannot be a translation for the plural version because it is the translation for "ils le regardent dans le miroir"
Both of those sentences have the same audio, and Duolingo isn't coded well for audio exercises since there can only be one correct answer even though there can be more than one correct answer for French, so I'm assuming it was just using both of them at the same time without realizing it