If the hard part is holding the crowd at the start, then it might be useful to know how many skills this takes, and therefore what skills you have left for the rest of the level. So if it helps, holding the crowd at the top takes:
one builder, and a digger to release at the end.
In case you're still stuck (and for anyone else who's interested), I've attached a replay.
As for the glitch tag, I'd say technically the solution does use a glitch, but because it's just incidental (you're not actually using it to get through the steel barrier), then maybe it doesn't warrant the glitch tag.
Also, before I forget again, thanks LemSteven for updating the results