First off, you grab the LIGHT GEM off the floor. M. BISON questions you on its use; is it some kind of light source? No. No, it isn't. The LIGHT GEM (hereafter referred to as the STEALTH LEVEL INDICATOR GEM (but not as the S.L.I.G., because that sounds dumb)) is quite similar to the "LIGHT GEM"
from the hit video game series "THIEF," which is your favorite game of all time. Well, the second one, actually. GARRETT is so dreamy.... Anyway, the STEALTH LEVEL INDICATOR GEM shows how hidden you are. This particular model has four settings, ranging from "OH CRAP I'M DEAD MEAT" YELLOW to "I'M A BETTER NINJA THAN A CERTAIN DOCTOR" BLACK. So, that being explained (summary: the gem shows how hidden you are), you place it in your CLEAVAGE so that it's always easy for you to see.
Next, you dart back into the UNDERWATER TUNNEL and grab the STOP SIGN, combining it with your TRAFFIC CONE to make a... STOP SIGN ON A TRAFFIC CONE. You stick it at the top of the STAIRS and hurry on.
You scoop up the NINJA STARS, since LATE NINJA ELLIOT doesn't seem to need them. But you give him your WALKIE TALKIE in exchange.
The footsteps coming up the STAIRS are getting louder!
You use your SCREWDRIVER to remove the SCREWS on the FLOOR GRATE and pry it open. It's not as deep as you anticipated, so you can just hop in and crouch. It's ninja enough for your STEALTH LEVEL INDICATOR GEM to read BLACK, so you're good and hidden. M. BISON hides with the simple expedient of BEING A STUFFED ANIMAL.
A large HELMETED CANDAEMON (with a DRILL ARM) and two smaller CAND...IMPS(?) have reached the top of the STAIRS. They stop at the STOP SIGN that you erected and proceed to poke at it. They seem perplexed and chat quietly among themselves about how to proceed. They appear at least vaguely threatening, but it doesn't look like they have any intention of turning around any time soon... but you can't be sure....
Should you continue hiding? Or explore the VENT? Or come out and sneak off? Or, really, anything at all? I mean, your options are TECHNICALLY STAGGERING!