Symplectic Monodromy Across Collision Walls in a Genus-Three Two-Pair Pencil

We classify connected geometric monodromy for an explicit genus-three hyperelliptic pencil with two moving pairs of branch points, over all admissible complex values of a parameter beta. The connected group is Sp6 outside the reflection parameter beta = 12, where it is Sp2 x Sp4. The proof uses actual based Picard--Lefschetz meridians, integral eight-strand braid transport, finite Lie-algebra certificates, and complex-parameter continuation. At certain collision strata the binary Lie algebra has dimension 20 while characteristic-zero monodromy has full dimension 21. Nonordinary triple-root fibres are bypassed rather than counted as ordinary meridian generators. The accompanying Research/QA archive contains exact certificates, independent replay scripts, and frozen source snapshots. The theorem concerns the specified family and the connected Zariski closure over Q2, not all two-pair families or the full integral symplectic group.