Possible Clues:

• Air of seriousness, consequence
• Dignity, solemnity
• At last, it's a failure to lose bearing in dead end with dignified manner
• Dignity — informer briefly clutches Bible with it
• Seriousness — sobriety
• Weight of a vast rig collapsing
• Serious quality in bearing and appearance
• Most of shop opened by key that's cut? Serious stuff
• Grip loses power holding a 6 tonne weight
• Seriousness of life once besieged by almost complete apprehension