Spam testing

I ran a test on one of my sites, using a backlink service and it subsequently vanished from the first page. Using this I am going to test it on other sites. Question is:

If site b (not mine) doesn't vanish, what does this mean?
If site b (ranks better for said keyphrase) why did mine disappear
If site b disappears (I can use this against more sites)
What is the limit for new links over time, how can Google determine whether or not this is legit? Also see above questions.

Once I have some more answers I will ask more questions, such as is Google one huge spy tool which tracks my footprints?

Said keyphrase isn't that competitive and is part of a competition. So I am doing a lot of testing.

You need to test on more than 2 sites to determine the results.
But in general :
backlinks are not something that get you banned in general it's usually content (of course if you have crappy content and spam the hell out of it ->inst bann).
the speed of your campaign should look natural (not 1k links each day from the start of your mini page).
you need to keep spamming to keep your ranking

btw. this just represents a normal website (continous linkbuilding, slow start then speeding up etc. )

ive noticed my pages vanishing for keyterm when i get a bunch of links, so want to test it on a competitors site.