The kid in the ice cream parlor told Dr. Bellows that he had just missed Major Nelson but Major Nelson was there the night before, not the same night.
In the beginning, you can see that the vacuum is not on because the vacuum bag is not inflated had it been on the vacuum bag would look like a balloon.
Dr. Bellows wishes that Tony and Roger would tell the truth so they do but when the argument gets overboard he tells them to stop arguing but he should have wished them to stop arguing in order to continue with the plot.