If a military operative you would possibly place explosive devices in several different areas, as they do not always go off as planned.
Wait, what about "Military Precision"? You mean military hardware sometimes fails? I better call my Congressman, this is shocking news. Shocking, I say!
But since Andy_Ross was in the RN, and hence a "military operative", why would one of his counterparts do anything different than what he stated as being the best/easiest way to put a ship on the bottom? They don't just hand explosives to any one, training is required, and not just the safe use of the materials, but what kind of charge to use, and placement.
If you are a robber you might place a few explosives around a safe with the sole intention of grabbing whatever you think the contents were.
No. If you're an idiot, yes. But no.
There are plenty of ways to crack a safe without explosives, depending on the safe. Some safes can't be opened without explosives without destroying the contents. And more burglars will steal the safe to open it later with tools, not explosives. I can't overstate what a big deal explosives are in the real world, and how experts don't just slap them on doors, and locks like refrigerator magnets. I've watched EOD crews work at Fort Ord clearing old munitions. There is no screwing around.
Were you a hostile military operative working in a team and your aim was to destroy the vessel you would almost certainly attack on more than one front to be certain the job is done.
If you're a hostile military team, wouldn't it be smarter to just find the truck, and hide in that truck, wait until the ship reaches port, kill the driver, and put the truck on the next ferry back to Estonia? Or track down the smuggler to his cabin, quietly kill him, and recover the whatchymacallit, instead of sinking the ship...that you're currently on...sailing in bad weather...?
How are you from the same island as the SBS, and James Bond?