, your little idea of shooting the floor at Fajo's feet has already been refuted in this thread.
The main problem is that Data doesn't know all the means that Fajo has at his disposal. Data has already been surprised. What we do know is that once he recaptures Data, he will increase his security. The more chances Data takes at that moment, the worse his position.
Fajo believes that Data will not harm him. Firing warning shots will therefore have no effect; Fajo will believe that the threat is empty.
On the other hand, if Data fires in proximity, he could accidentally hurt Fajo. Knowing he could get hurt accidentally, Fajo will simply activate one his failsafes, which we can assume he has based on his pattern to date, to recapture Data.
Or, it could ricochet and kill Fajo or someone actually more innocent.
Fajo is vulnerable only because he is gloating in this moment when he believes Data will not fire. Change any of that, and it's Data who becomes vulnerable.
Finally, how much charge is there on the disruptor? Can Data be sure that there is even enough to fire it more than once or just a small number of times?
Your little idea depends on being able to fire the weapon a large number of times, and it offers too many chances to Fajo. Data was never going to have a better opportunity in the foreseeable future to neutralize this brutal danger to the galaxy.