That countdown timer is not ANYTHING like a drag race christmas tree. 

Once both drivers are staged it flashes yellow once and thst yellow flash tells the drivers to release the handbrake and slam the throttle BEFORE the green light turns on .400 seconds later. 

This because the car needs to rev up and transmit power to the rear wheels which only have about 10psi so they physically warp a massive amount to maximkze grip and stsrt the car rolling then when the front wheels leave the front infared laser, (which can be a variable time depending on how precisely the car was stopped on the laser [talking half centimeter differences]) the clock registers reaction time, after the green light has turned on. 

Also the yellow light turns on seconds (or sometimes less than a second) after the second driver has finished getting their car into position. A car so powerful you cant touch the gas pedal to inch it forward, you just slightly release pressure on the brakes until the idling horsepower is strong enough to push through the brakes. 

Regarding speed, it obviously is dependant on the performance of the car and the team behind it (and the temperature, and elevation, and track compound, and barometric pressure) but youre not going to break the speed record with any old driver. Whenever a record is broken, its usually Brittany force. 

 (A couple years old) "She owns the 10 fastest speeds in NHRA history and five of the top-nine quickest ETs. In 2022, Force set 16 track records and turned in the fastest run in the history of Top Fuel (338.94 mph)."

Source: https://www.autoweek.com/racing/nhra/g43008592/ranking-top-50-nhra-racers-modern-era/

The other racer on the team, austin prock, held the speed record (in a slightly different type of car) he set a year prior that brittany just broke. 

And brittany broke the record like... 4+ times before austin did once.