Crash at the beginning of Surface Tension

As I go through the tunnel to start Surface Tension, the game crashes 100% of the time. I’ve had to forsake my only save file and start over from Questionable Ethics.

Edit: Even restarting doesn’t fix the problem. I can’t get past Surface Tension at all.
hl2_4104_crash_2012_9_15T13_16_39C0.mdmp (107 KB)

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.