There was no FA Cup hangover as substitute Shaun Batt struck the winner six minutes from time to give the Lions a first home league win since New Year's Day and move them up to 16th in the table, although still only four points above the drop zone.
"It was a huge relief, especially after the other results tonight," said Gallen.
"In the second half I thought the whole club seemed to galvanise.
"We did not have too many chances but the one clear-cut one we did get, Shaun put in.
"I haven't got a clue what the safety figure is, I've never seen anything like the division this year.
"But a win against Huddersfield on Saturday would take us away from them and up to 58 points, and then we might be all right."