The former Mariner found himself the target of the 1,000 or so travelling fans abuse throughout the game but wasted the chance to silence his critics from 12 yards.
Speaking to the Grimsby Telegraph, Gallimore admitting he's still at a loss to what went wrong. But has vowed to have the last laugh come May.
"I was devastated. I gave Ade (Davison) too much respect. I thought he knew where I was going to put it and I had to get it spot on, in the corner,"Gallimore told the newspaper.
"It's the first one I've ever missed. I took them all the time at Carlisle and took two or three for Grimsby in shoot-outs and always scored.
"I thought of too many things before I took it; probably because it was Grimsby.
"I didn't know what to do with myself when I missed. I must have taken it 1,000 times since. If only this, if only that.
"It would have been the perfect way to end the game. It would have been nice to shut the fans up a bit.
"We'll just have to win promotion and see if that shuts them up at the end of the season."