It’s the lack of traffic he notices more than anything.
Stepping out of the TARDIS, the stillness is overwhelming. This quiet is just so…alien. Certainly for twentieth century London. The Doctor looks around at the deserted, grim buildings, the empty streets, and closes the TARDIS door.
Something is wrong.
London is never this empty and motionless. There is always movement, always noise, always traffic. This city is too still, too silent, too…dead. Something evil has happened here. Something he must fix.
Time to get to work.
The Doctor walks off down the empty street. Cold, alien eyes watch him go.