@B.B.:
Well, since you pre-emptively put in the request, let's see here.....if Woofer fails his composure check and is incapacitated by the gas, then you can try to lift him and push him over. First you'd have to resist gas too like you said, and since you're small, that's gonna be a lift over the head which is 5kg/point of strength, so in your case 15kg + 5kg/hit on a strength 3 + body 3 test. We'll say Woofer is about 75kg. That's gonna require 12 hits on the test....which is a quite a longshot. You're also all out of Edge. (I realize there's a debate about burning permanent Edge but i'm of the mind that if someone wants to burn Edge, they need to have at least one Edge point in their pool. i.e., if the pool is depleted, Edge can't be used for anything, not even burning.)
@Everyone
So we'll just base the outcome all on Woofer's rolls. The idea is that a failed composure test is a split second hesitation which is enough to get a whif of gas....but would be hard for everyone that's jumping together to notice before they took the jump. In Woofer's case it would mean for me that he made sure Mercedes jumped through first, i.e. took his eye off the ball.....not that he pussed-out.