Horrace is tough so I guess I can only give you basic advice.
You have to be very careful killing those bugs so that you don't harm the patient so take careful aim with that; the best time to hit them is right after they change direction I find. Following right behind them is a good tact.
Put out all fires as quickly as possible, and remember you need to soak up blood first to extinguish them.
The nests will be right below where the last big spider was killed so you could shave a few seconds off there if you get the hang of it.
Best of luck, I'll post more if I can remember Horrace file 1 any better.
Someone's far less popular main.