Found on http://www.telltalegames.com/
Act IV (and a half): Tunnel chase! (Wallace and Gromit)
Wallace takes the tanker into a tunnel, with the Queen bee hot on their heels. Gromit's still in the back, and has managed to convert the truck's spigot into a honey-firing cannon. However, hitting the queen with honey doesn't stop her for very long. When you exit the view with Gromit, you will switch back to controlling Wallace, who is driving the vehicle. Adjust the radio until it switches to a station featuring two women performing a comedy skit. The bee seems amused by this station and frequently laughs with its mouth wide open. However, it's not enough to stop her pursuit.
Next, open the valve that's just outside the passenger-side door and pour the miracle growth formula into the honey tank. Switch back to Gromit and have him fire the cannon at the queen, making sure to time your fire for when the queen bee is laughing. If you're successful, the queen will swallow the honey and start to grow until she's too wide to fit through the tunnel exit, allowing Wallace and Gromit to escape!
That wraps things up for Fright of the Bumblebees. All that's left is for Wallace to formulate an antidote to the growth serum, which he will invariably use on himself by mistake. See you at The Last Resort!