And how many Unsullied were lost really? 15 or so?

Insurgent/guerrilla tactics like that are great for taking tiny nibbles out of an occupying force (see Iraq, Afghanistan, Vietnam.. etc) but I'm pretty sure although Dany would rather her army commander and closest advisor weren't in harm's way unnecessarily, she won't mind losing 15 of her 8,000 Unsullied in order to bring the SoH above ground so they can be properly squashed.

Have we all forgotten her line from the last episode?

"Angry snakes lash out; makes chopping their heads off that much easier"