The key thing to think about during these sorts of decision points is not only likelihood of success, but what success gets you. They always trick you with these branching paths that way. Fun fact, did you know that a couple worlds back, Eska used to write choose your own adventure novels for entertainment? It was the high tech one where she really got into the scarab bots, so all the choices were like "hotwire the keypad with your trusty multi-tool" and "use your superior intellect to trap the guard robot in a logic puzzle" but she really got into it for a while, and the Riders even had some fun setting them up and acting them out as a party game (Eska would umpire, of course, since she was far too skillful and knowledgeable to be able to participate fairly). 

Oh right, the Spriggans. The point was that the Kazelia had learned a key lesson, which is that you couldn't just go for success in these adventures, you needed to push for the best outcome. If you stumbled into something you couldn't handle, well, you had to extract as painlessly as possible and come back with the right tools. So here, even though spear-fighting was the easy choice, Kazelia knew that stalling the spriggans would just lead to them grouping up with their nightmare commander and coming at her in force. She could try to run, but that has never been her strength, especially with all these tricky vines. So, of course, she's going to impersonate the commander. If she's quick about it, she'll get her own team of support Spriggans, and at the very least, she'll confuse them long enough to make the whole thing a non-factor in the victory equation!

[Rolling wisdom with despair: [s]5[/s] 2, 1 +1=4.]

What Kazelia hadn't counted on, of course, was that she really didn't quite have the voice control down yet. Attempting to mimic the rustling sound they make while doing speech caused her braces to grate painfully and led to her attempted "Obey me, Spriggans, I am your leader!" to come out more like "Okay me, Sthpriggens, I am your theater!"

...Oops