As smart as the Doctor is maybe. The thing is only extreme heat can actually melt a T-1000 and it took the T-1000 along time to die in the lake of hot steel...... I guess if the Doctor got ahold of a hot enough blow torch he possibly could. if he kep blowing the extreme heat on the T-1000 for along enough period of time.
He's a god, I will say that. The T-1000's finger works faster than a speeding bullet, he can shoot his metal sharp blades in the doctor, or shapeshift into a hot woman and do what the T-1001 Did in TSCC.
I'm telling ya, these liquid models aint nobody to be messed with.