Putting all the clues together, the aligner comes up with the following alignment without actually having to know the two languages: the corridors korridorerna are jumping myllrar with av them dem However, looking at the sentence pair again, a second aligner with knowledge of both languages might realize that the verbs myllrar (English: swarm) and jumping do not really correspond to each other in isolation and that the expressions are rather idiomatic in both languages.
the second aligner might decide to link the whole expression "are jumping with" to the Swedish translation of "myllrar av".