起床 and 就寝: before a wake-up signal and bedtime
Follow the stated rising and bedtime hours, waking before a signal, and reading before bed. Keep each earlier action related to its own reference event.
Rising on a trip and waking before a signal
「旅行の日は朝五時に起床しました。」 means “We woke up at five in the morning on the day of the trip.” The example gives five in the morning as the rising time on the trip day. It is a time in that particular travel context rather than a general recommendation.
「起床の合図が鳴る前に目が覚めた。」 means “I awoke before the wake-up signal sounded.” Waking happened before the rising signal sounded. 起床 identifies the purpose of the signal, while 目が覚めた states the awakening itself.
Going to bed and reading beforehand
「旅行中は十時に就寝した。」 means “I went to bed at ten during the trip.” 就寝した describes going to bed at ten during the trip. The bedtime is given without specifying when actual sleep began.
「就寝前に短い小説を読む。」 means “I read a short novel before sleeping.” The short-novel reading comes before bedtime. 就寝前 places the reading earlier than going to bed, rather than after falling asleep.
An earlier action and its reference event
In the signal example, 合図が鳴る is the reference event and awakening comes before it. Saying that the signal caused the awakening would change the stated order.
In the novel example, going to bed is the reference point for an earlier activity. Waking before a signal and reading before bed each use a different reference event; the two travel times do not establish a duration of actual sleep.
In what order did awakening and the wake-up signal occur, and does the sentence say the signal caused the awakening?
Show the answer and why
Awakening came before the signal. 起床の合図が鳴る前 marks that earlier timing, so the sentence does not present the signal as the cause of waking.