This is one of the dumbest things I've read in this thread, certainly in the top four.
There were no explosions.
The Spetsnaz have access to quality fake documents to just about any European country, so getting a truck bomb on a ferry back in 1994 would not have been much of a problem had they wanted to do something dumb.
The Russians didn't sink the Estonia.
There are hundreds of surveyed shipwrecks with plenty of holes caused by explosives, shells, torpedoes, and mines. The Estonia is not one of them.
Smuggling of Soviet/Russian secret hardware continued after the Estonia sank.
Had there actually been some vital piece of Russian state secrets onboard the Estonia the Russian navy would have intercepted her with surface ships, escorted her to a Russian port, and searched the ship. The resulting public relations fiasco would be more than enough to make the west cool their jets. This is how Russia had acted in the past along with China, North Korea, the UK, and the USA.