Whenever the Praetor attacks, it pumps it's piston, which releases steam. To efficiently dodge it's close range attack, simply execute an Impulse movement when the Praetor releases steam to get as far as possible.
When the Praetor executes a long range attack, it pumps it's piston and creates fire on it's attacking hand. Before it attacks, it pulls back the attacking hand. Before pulling back it's hand it will continue to lock onto the Warmech until it pulls back the attacking hand. Execute the Impulse movement as it pulls back the hand to dodge the attack efficiently.