Possible Clues:

• Don't want Berklee teacher to notice your this
• Seaman oddly seeing crew showing non-attendance
• Time away
• Lack of belief initially in disorganised seance
• Scene changed after sailor gets leave
• Cab seen breaking down -- it's registered by someone not here
• A Bishop observed to be half-hearted attracts church attendance? No!
• Lack of muscles means crew regularly lost
• Perfect attendance spoiler
• Leave scene contaminated by sailor