Portal Stories: Mel Test Chamber 04

Chamber 04 (also known as Virgil-04) is the fifth map of the third chapter.

Video Walkthrough
NOTE: This video shows the whole Third Chapter in Story mode.

Trivia

 * Before entering the work in-progress test chamber, Virgil says "generally they (test chambers) need to be tested at least three times before they're finalized. Some people just can't count further than that I guess". This is a reference to the running joke that Valve can't count to three.
 * The track played during most of this chamber is called Transitional Period