Credit to Twitch streamer Dicedeus. Some of his routing definitely made certain sections quicker, like simply sprinting past the turret in the Reservoir level, without which achieving sub 1 hour 30 would have been a lot harder.

Sadly despite not dying at any point during this run, there were a handful of mistakes that overall cost me about a minute and a half. The main one being incorrectly throwing a frag grenade at the start of the Reservoir level which killed the guard I needed to interrogate.

Sum of best is 1:28:16, I think with the inclusion of some additional route changes a high 1:27:xx is possible providing the rest of the run goes smoothly.