We have enough events, because in this case it is appropriate to model the actual random event as 'million miles driven' with a chance of fire happening or not happening. Gasoline cars have a mean of 0.05 fires per million miles, and given the current Tesla data, the mean is 0.01 fires per million miles. I'm not taking out a calculator, but it would come out to an extremely low (0.0001%) the 'true' fire chance is the 0.05 gas car rate or higher; the 95% confidence interval should be 0.01 +- 0.02 or tighter, so still twice better than gas cars.

For an exaggerated example, if Tesla had driven a billion miles and had 0 fires, you shouldn't say that there's not enough data - you definitely would have enough data to say that the chance of fire is below the gas-car rate of 5 fires per 100 million miles.