For those that are unaware, all rockets then rapidly increase their G. For example the Saturn V had 1.20 g at takeoff but climed up to 4-ish: http://www.braeunig.us/apollo/saturnV.htm

Someone on the Saturn V started experiencing more G than the Roadster about a minute into the launch.

When you move a building-sized fuel tank under its own thrust it's going to start off slow, but accelerate as more fuel is burned.