The shock in Matthew 8 is that sons of the kingdom are thrown out while nations recline with Abraham.
Darkness outside a lit feast is covenant exclusion. Gnashing of teeth is rage and grief, not a geology of the underworld.
Matthew uses the cluster for people who assumed pedigree guaranteed a seat. Matthew 22 and 25 reuse it for wedding guests and worthless servants.
Those who claimed the table by flesh watched Gentiles take the seats while their city went dark.
The feast is the New Covenant table. The darkness was the exile of an order that refused the Host.