yeh Bundy,
i reckon it would go down/ the air in the tyre would contract over time as it cools.
but as TB said, they have only got the tyre to bead properly/ bead to seal on the rim enough to then be inflated.
you’ll find they most likely used an air compressor to inflate it to the correct pressure.
as with a large tyre like that, you would be hard pressed to get the tyre bead to seal enough to inflate it with the travel compressor they would have taken with them.
brake cleaner would work well… aerosol can degreaser too…..
you would have to light the fluid/ mist in the tyre pretty soon after you spray it into the tyre, otherwise it wouldn’t have quite the same expansion / explosion as if you let it evaporate too much.
hairspray would work ok i guess, that’s what they used to use in the spud guns.