It looked like Vale would become the first team to take any points off the O's this season as Louis Dodds and Jennison Myrie-Willams scored either side of two goals by David Mooney, but Kevin Lisbie made it six wins out of six for Russell Slade's side with the decisive strike after 88 minutes.
Adams said: "We are bitterly disappointed with the result for sure but we can take a lot of positives from this game.
"We didn't want to come here, sit back and try and nick a result. We had a positive approach to the game and it looked as if we were going to get something out of it.
"Having said that some of the goals we conceded were absolutely criminal. If we are going to make mistakes like that, especially against the better teams, then we are going to get punished - and they punished us.
"We kept a clean sheet at Carlisle last week but with the greatest respect, Carlisle and Leyton Orient are two different propositions.
"I didn't want to come here, sit back and try and frustrate them because I know Orient have got decent players. They've got good forwards who are going to cause you problems anyway.
"I thought our best way was to go out and attack them, which we did. We've shown that going forward we will cause teams problems but it doesn't matter who you play, if you are going to give them three goals to win a game of football then you've got no chance yourselves."