OF COURSE, THE RADIOACTIVE GAS WAS REVEALED TO HAVE A DELAYED REACTION.
SO, THEREFORE, ANYONE WHO WAS EXPOSED TO THE gas WOULD NOT get effects TILL THE NEXT DAY.
SINCE Ernie & Tim were in contact with said radioactive gas, they WOULD NOT get THEIR SIZE CHANGE effects TILL THE NEXT DAY.
so they carried on with their film as if nothing had happened.
That night, they went to bed, still unaware they'd been affected by the radioactive gas.
But with the radioactive gas, they had no idea about the delay.
Would the changes happen overnight?
Or wouldn't they actually start till later the next day?