What sleep disorder is indicated by Mr. Reid's sudden lapse into REM sleep during an argument?

Mr. Reid's sudden lapse into REM sleep during an argument is indicative of narcolepsy, a neurological disorder that affects sleep regulation. Narcolepsy is characterized by excessive daytime sleepiness and unexpected episodes of falling asleep, which can happen at any time, including during emotional or stressful situations such as an argument.

These sudden sleep attacks can lead to entering REM sleep directly from wakefulness, which is a hallmark symptom of narcolepsy, distinguishing it from other sleep disorders.

In contrast, insomnia refers to difficulty falling or staying asleep, sleep apnea involves interrupted breathing during sleep, and parasomnias are undesirable physical or verbal behaviors during sleep, such as sleepwalking or night terrors, none of which specifically account for Mr. Reid's behavior during the argument.