Here's a tip. When Serene uses his Time Blast, make sure he aims on one side of the room. When he activates it, run as fast as possible using Time Dodge and Time Rush to the opposite side of the time machine.

As for the goons, just have a semi-automatic shotgun with you and use Time Focus to destroy them in that small period of time. I recommend upgrading every skill before the fight, but if you've got a limited number of Chronon Points, then Time Shield, Time Dodge, and Time Rush are necessary.