Dougie Freedman netted deep into stoppage time of the first leg at Elland Road to give the Whites hope for the Burnton Park return, although they still trail 2-1 after a below-par display.
"We would have been disappointed with 2-0, but it wouldn't have been a case of surrendering," said McAllister.
"At 2-0 down I felt we were still in the tie, but just getting that goal makes it slightly different.
"It was a real open game. It was box-to-box and there will be some tired legs come the last 10-15 minutes at Carlisle.
"It's game on and I'm looking forward to it. It's going to be exciting up there. It just puts a different perspective on it now, scoring so late on."