Oldham went ahead after 37 minutes as Harkins' chipped cross was flicked into the far corner by the head of Adam Lockwood.
A superb individual goal by Carruthers brought MK Dons level early in the second half as he rode two challenges and side-stepped another before finishing into the bottom corner.
Genseric Kusunga was sent off after being shown a second yellow card for his challenge on Stephen Gleeson with 25 minutes left and the hosts went on to snatch the points when Mark Oxley pushed Carruthers' cross into the path of Reeves.
Robinson said: "It's great to win games like that - there's nothing like it for the fans or the professionals as well.
"I celebrated like Brian Kidd almost when it went in - I slipped over three times, pulled my groin, dirtied my trousers!
"It may have looked like we were half-hearted in the first half, which wasn't in the game-plan at all.
"I had a bit of a go at Samir at half-time - I just felt he was poor by his standards - and I said to him if he wants to be a good player then he needs to score goals and he shoved one right up me there!
"Instead of worrying about getting in the play-offs, our mindset at the moment is to worry about the next game against Preston and then the game after that.
"I think that if we accumulate enough points, we'll cross that bridge when we come to it."
- Sports & Recreation
- Samir Carruthers
- MK Dons