The big Rovers centre-back unleashed a 25-yard volley 10 minutes from time to earn a point from an entertaining game.
The Gills had taken a 38th minute lead when John Nutter powerfully headed in Nicky Southall’s far post cross from the right.
Rovers could have been three up in the early stages, but wasted their chances in another disappointing home display.
Top scorer Rickie Lambert might have had a hat-trick, but he was twice denied by fine saves from Derek Stillie and could find no way past the impressive Gills keeper.
The visitors fought so hard to protect the lead, but had no answer to Elliott’s strike and now need at least four points from their remaining two games to have any chance of staying up.