Background
A determined Templar Squad descends into the tunnels below Vestmarch to block an attack vector.
Xenos are boiling up from the under-ground storage chambers in huge numbers. The aliens have found a way through from beneath the fortress.
The force commander has deemed it critical to stem the tide of xenos coming from the storage-depths, to allow the Templar forces to focus on the frontal attack.
Your squad has geared up with hyrdo-detonators and is assigned to enter the lower storage chambers, and identify a viable place to collapse the tunnels used by the xenos.