Movement. A target standing still too long was easily acquired. Maneuverability for most of their mechs was the advantage; a Thunderbolt was a big, dangerous mech of normal maneuverability in its class. Urbanmechs and Panthers were heavy on the guns and armor, but slower. 

The FedComs had faster mechs, but they had to actually move to use that advantage. The Thunderbolt might not have him, but it would eventually find the angle.

And so Mattlov pushed the Shadow Hawk off the position of temporary safety as the Thunderbolt was already in motion, moving to the left of the big mech even as it started to turn the corner on the position and obtain the angle with the PPC. 

He risked the rake of medium laser fire to do that. A laser fired for a small amount of time, though good marksmen strove to keep the lasers on target. Pulse lasers were easier-- they fired more power in a quicker fashion, often landing more accurately in one location. Betting on the idea that a periphery pilot would be using the old fashioned kind, he swung his arms and torso around to try and spread some of that damage across the right arm and right torso, to avoid a penetration of internal components.

The Thunderbolt also had a blind spot there, from its LRM, that prevented the pilot from easily seeing what was going on to his right. That was an advantage as well. 

Mattlov could tell that he took some damage, but he saw the big mech was starting to vent heat, even as he opened up the distance. This made him vulnerable to LRM and PPC fire, but he had the advantage of agility.

He even fired the jets...and on the landing, raked with his own large laser fire at the Thunderbolt's arm. He kept an eye on his own heat, but the Shadow Hawk had upgraded heat sinks and the design was designed to run cool; if the laser started to spike the heat, and the Star League-era ERLL's did that, he could go back to the autocannon. But he was saving it, because the ammo it loaded was an experimental type, armor piercing and heavier than the normal...which meant that his bins carried less of it to keep the weight from straining the mech.

So far, a piece of the TDR's left torso ripped off from a pair of autocannon hits, and the arm scarred from laser fire at the cost of three medium laser hits to his own right torso and arm. But he was forcing the slower mech to turn. The bastard had interior lines to compensate for Mattlov's speed. 

The hills they were in and out of had different outcroppings and folds in the land, and his roll-out maneuver put him north of his enemy. It was possible to fire the jets and land behind an outcropping for cover. But he'd have to do it all over again. Instead, he aimed to position himself between the TDR and the water. He'd have to take more fire for it, but at least he'd force his enemy into the rocks. And his enemy wasn't dissipating Steelton's heat all that well...