Shhh! No verbal spells aloud.

[Xarlen]

Dispel Magic?

 

[bret]

I hope you know that a Wall of Force is immune to Dispel Magic...

From the SRD:
...and it is totally unaffected by most spells, including dispel magic. However, disintegrate immediately destroys it, as does a rod of cancellation, a sphere of annihilation, and Mordenkainen?s disjunction.

 

[Xarlen]

Well, the caster was going to destroy it anyways when he buffed up. Too late to retcon it anywho...

 

[Shard O'Glase]

Sorry, I think my players would kick me in the monkey for that. It reeks of cheddar.

Good thought, though. How does my above thought look?

Really, we've ruled that ventriliquism works that way for a long time. Defense should be easier than offense IMO, and so you get a nice defense to silent spell as a 1st level spell. Before 3e they had a 1st level spell specifically for silence(probably because they realised how broke it was) called vocalize, for us ventriliquism is out substitute.I guess with the silent feat they didn't want the vocalize spell, though I don't think the feat is a good fix for how broke the spell is.(though in this case with a failed save I'm not as bothered, it could jsut as easily been a hold person that ended the fight, it's the cast it on the fighter and he charges ahead thing that really wrecks the spell, everyone in the area should just get a save)

Now the potion thing might not work technically, but you could have an amulet/wand etc.