Tongue, I must put you into a butterwoman's mouth, and buy myself another of Bajazet's mule, if you prattle me into these perils.
A bunch of Bertram's men pretending they are not Bertram's men gang up on Parolles and kidnap him. If I've got it straight the point is to test his loyalty. In the meantime the spurned Helena has something up her sleeve for good old Bertram and enlists Diana to assist. Which results in the latter two trading a whole lot of sweet nothings and generally slowing down the pace.
Parolles shows what he's made of by singing like a canary at the first hint of duress. I'm unclear at this point if he knows who his captors are but it's not the first time I've been baffled and probably won't be the last. I've also missed a key plot point somewhere as it now seems that many of the players think Helena is dead. Spoiler alert - she ain't.