Previous comments regarding the presence of an Ambulance seem's to be a precaution to me rather than anything urgent, otherwise we wouldn't have seen the slow measured build up to the nighttime CSI.
I'm sure people on here know but for anyone wondering why they wait until after dark to conduct CSI this will be helpful knowledge from someone in forensics and helps understand what the the thought process of the forensic team will be.
"Before I started in forensics I thought using a flashlight even in a well lit room was crazy. But it actually works and I have truly found evidence because I chose to use the flashlight.. the oblique lighting that you apply with your flashlight creates contrast against a background. This contrast with the shadows lets you find things you might not other wise notice. Fingerprints are a perfect example where in a perfectly lit room with direct lighting you may not see the fingerprints. But apply oblique lighting and taking your time and you can where there are possible fingerprints to apply your powder and enhance.
The light also serves to centre your concentration while you are searching. I have had the occasion to be in extremely busy crime scenes with a lot of different things going on evidence wise. With the flashlight, it Centre’s your attention and highlights what you are seeing. The human eye and brain can sometimes play tricks and fill in blanks with what it believes should be there. ( example: sitting with a deceased person long enough that you swear you saw them breath because that is what your brain is used to)
Foot prints, fine blood spray against certain materials, small items on a rug.
So it seems redundant but really it has its purpose"
