Hey Guys,
This has been discussed many times, I've collected here pretty much everything regarding it!
Best bet is slightly adjusting you tactics, or if that fails a speed mod is an option. I to struggled with this door, but by moving before the blast dissipates I was able to do it, it should also be noted that being encumbered will prevent you succeeding, also some people have been able to succeed by reducing their graphics settings.
Videos, (these give a lot of help)
viewtopic.php?f=13&t=1572&p=15574#p15574
My own difficulties with this! (many useful hints)
viewtopic.php?f=12&t=1697&p=16842#p16842
Cheat Engine (use at own risk!)
viewtopic.php?f=3&t=1688&hilit=speed&start=40#p18696
Fan made timer patch,(adjusting speed may cause other issues so only do this is you feel you must)
viewtopic.php?f=3&t=1688&hilit=speed&start=40#p18684
One last thing to note, you don't have to get behind the door, it is for completionists only and isn't meant to be easy. (Personally I didn't find the items that useful for my party)
Good luck!
Daniel.