The very concept of Micro is a nightmare. Imagine being shrunken down to half an inch tall by a psychopathic businessman and then dropped in a rain forest, where once-harmless insects and other bugs are now terrifying Kaiju. You can't even call for help because the aforementioned businessman will find you and stomp you to death himself.
The death of Jarel Kinsky, the engineer who was unfortunate enough to be in the tensor generator room when Vin Drake decided to use it to dispose of the grad students, is horrific. He makes the mistake of running past the entrance of an ant colony, which causes the soldier ants to attack him. They literally tear him limb from limb and eventually decapitate him before carrying him piece by piece back to the colony to be eaten. To make it even worse, it's revealed that he has a wife and children.
Telius's death is also very gruesome. He's attacked by a spider- and not just any spider, a gigantic huntsman spider. To the half-inch-tall humans, it's literally the size of a house. When it attacks Telius, it injects him with poison that literally digests and melts him from the inside out. The book spares no detail in telling us how the poison affects him and causes his organs to leak out, describing it as "Ebola in 30 seconds."
What happens to Danny's arm. A parasitic wasp lays its eggs in his arm, also injecting an anesthesia so he can't actually feel what's happening to him. Eventually, his arm becomes so swollen and the skin becomes so taut and transparent that the characters can actually see the wasp maggots feasting on his arm. Just... ugh.
. To the half-inch-tall humans, it's literally the size of a house. When it attacks Telius, it injects him with poison that literally digests and melts him from the inside out. The book spares no detail in telling us how the poison affects him and causes his organs to leak out, describing it as "Ebola in 30 seconds."