>>137328539Maekawa Master Plan! A lot of it's unfortunately just me making guesses and filling in the gaps. We know Tower was friends or at least interacted with Maria on the ARC and was there when GUN attacked. The fact that there's survivors means GUN had a successful cover story. We also know the Artificial Chaos broke out so saying one of the experiments killed the researchers makes sense.
We know Tower hates Shadow, blaming him for Maria's death so it's fair to say the public were only told an "incident" occurred on the ARC, the scientists were told an experiment escaped, and GUN's reports would've blamed it on Shadow.
We also know Tower fears Shadow enough that when he escaped from Prison Island he was willing to pin the blame on Sonic, a world-renowned hero.
Losing his childhood friend to a world-ending threat only to be saved by GUN soldiers probably had a massive effect on young Tower. My guess is it drove him to join GUN and rise up the ranks to prevent future tragedies.