How did Gollum get out of Moria?

[BalrogRingDestroyer]

After the snake lake monster destroyed the Mellon Gate, Gandalf said that there was only one way out, on the other side. However, Gandalf had destroyed that bridge in the Balrog fight. So how did Gollum get out?

 

[Olorgando]

After the snake lake monster destroyed the Mellon Gate, Gandalf said that there was only one way out, on the other side. However, Gandalf had destroyed that bridge in the Balrog fight. So how did Gollum get out?

You will recall that despite the destroyed bridge, the Fellowship was pursued by Orcs from Moria. Fortresses practically always had "side exits / entrances", most probably inconspicuous, even camouflaged. Think of the sortie by Aragorn, Gimli and others from the keep of Helm's Deep against the forces of Saruman attacking the main gate.

 

[d4rk3lf]

It's either a possibility what our friend @Olorgando said, or Gollum had a perfect timing to jump on the falling Balrog, then bounce of it, to the other side.

 

[Sihtric]

Exactly! Like what @Olorgando said, that was definitely a possibility (especially because Khazad Dum was so vast!); adding on to that, after spending so long in the Misty Mountains, finding his way around a small part of Khazad Dum probably wouldn't have been too much of a challenge for Gollum-especially if he was so bent on finding Frodo and the Ring.