I don’t envy the fight that’s about to come.
Tunnel warfare is no joke. 
You’re deep underground, less clean air, fighting in darkness (if power to the lights is turned off) - worse if you lose your sense of direction, plus all the deafening sounds from gunfire and explosions, amplified lethality from grenades, little to no cover/restricted movement.
These salt mines are supposedly massive with several entrances/routes. You could be outflanked and not see it coming.