Either something is keeping them and they will come when they come, or all of them already passed through. Nothing you can do short of calling them to you (bad idea) will change that, and your current plan is unaffected unless they show up.
Continue to the generators and find Melisa.
None of them have a good answer for that, so they just keep going.
"We go right here," says Emmie, as they reach a t-junction.
"Huh," says Bina. "That's weird."
"What?" asks Kendra. "If this is another-"
"No, I - no - just - the water is moving."
"The water, it's flowing from this way, the way we're going. Can you feel it?"
"Err, no," says Emmie.
"I guess it's 'cause I'm wearing socks."
"A water main-line must have burst. With luck, this is just grey-water," says Emmie. "It doesn't smell like sewage. Still, getting a tetanus shot after this probably wouldn't be a bad idea."
"It's not sewage," says Kendra. "Or grey water. Bina, look at your breath."
Bina breaths out, and a cloud of vapour curls around her face.
"There's a crack down here somewhere."