As you watch, it becomes apparent that progress above the VENT would be... problematic. As more and more CANDIMPS (yeah, you're calling them that) file out from the STAIRS, you abandon the several CLEVER PLANS that you came up with to deal with them. Good lord, there's, like, seven of them! And there are more coming!
M. BISON seems to have things under control with his "hiding." You don't really have a choice right now as to whether you can bring him along. With any luck, he'll find a chance to slip away on his own and meet up with you. Good luck, LIEUTENANT. Godspeed.
You pocket the SCREWS that you had obviously been holding in your hand. You then duck down the duck. The duct. You meant the "duct."
You find yourself in some DIMLY LIT DUCTWORK. Above you is a LADDER to the VENT in the HUB ROOM. To your left is a PIT, descending into DARKNESS. You can't see the bottom. Further left, the DUCT continues. But again, there's a whole ton of DARKNESS (which you briefly consider attacking). Anything could be over there. Waiting. Watching. Wanting to eat your BRAINS.... Gah. Years of video game reflexes kick in. You are on HIGH ALERT for HEADCRABS.
To the right, you see a SMALL MOUSE and its associated MOUSE HOLE. How it gnawed through the metal of the DUCT, you have no idea. Aww. It's so cute. Beyond is a spinning FAN, and you can barely make out that there is another DUCT large enough for you to traverse behind it. What should you do?