Answer:
The dependent clause is "were fired, punished, or even killed." The transition word is "were."
Step-by-step explanation:
A dependent clause is one that depends on a complement so that it is able to convey a coherent and understandable meaning. This is because this type of clause is not able to transmit a complete thought, managing to establish a message alone.
If we look at the sentence shown in the question above, we will see that the clause "Workers who completed to the owners" is able to start and end a thought, being then the independent clause. While the "were fired, punished, or even killed" clause fails to start and end a thought, it is a dependent clause.
The transition word is the one that makes the connection between the two clauses in a sentence. In the sentence shown in the question above, the transition word is "were".