After the Russian Revolution mission, where you fight Dimitri's men in the warehouse, Roman calls you whispering, requesting that you meet him. When you do, you find him hiding in the trunk of a car. The recent events have really scared him. The two of you drive to his house, only to discover that it is on fire. Roman is sorrowful. You then drive to Roman's taxis depot, which is also on fire. Roman is very sorrowful and worked up. Head to Mallorie's house in Bohan, which will become the location of your new safehouse.
NOTE: Following this mission, Roman's taxi missions will be unavailable for the rest of the game.