The Millers dominated the opening exchanges and should have made more of their early advantage.
Lewis Grabban pounced on a deflection off Gulls right back Joe Oastler to open the scoring from a few yards out in the third minute.
Millers skipper Ryan Cresswell then headed the visitors 2-0 up from Danny Schofield’s ninth minute corner.
Billy Bodin scored his second goal in two games with an 11th minute strike from the edge of the box before Grabban grabbed his second goal of the game to restore Rotherham’s two-goal advantage.
Gareth Evans crossed from the left and Grabban got a deft flick on the cross to just take the ball out of Bobby Olejnik’s reach as the home keeper went full stretch.
Torquay were given another lifeline when Nicholson followed up his own shot to head over visiting keeper Conrad Logan in the 41st minute.
The home side got off to the perfect second-half start as Howe beat Cresswell before clipping the ball over Logan to make it 3-3 on 47 minutes.
Torquay came within a whisker of winning when Eunan O’Kane’s 70th minute free kick whistled just past the post from 20 yards. Then in the 90th minute, Bodin’s left-foot shot from 15 yards beat Logan and smashed off the upright.