I rarely do battles between beings from the same universe but this one felt okay. I don't think Voyageur's EMH will ever meet Data seeing as he is dead.
Data will have a phaser but it will be useless against the Doctor. Any physical attack from Data is powerless against the Doctor also.
Data has only one chance to "kill" the Doctor. If he can damage the mobile emitter, the Doctor would disappear since there are no holoemitters in my arena.
The Doctor can alter his density. His ability will work on Data. Data doesn't know about the mobile emitter so he wouldn't
try to damage it. The Doctor just has to phase into Data's chest to disrupt his systems. Data is superfast but he probably
wouldn't expect that kind of attack.
