ngb1066 has first hand experience so better placed to give his opinion.
Obviously firearms with or without silencers are not designed to be used at close range in farmhouses complete with furnishing and soft furnishings. Such experiments need to be carried out on a like-for-like basis otherwise a complete waste of time.
A silencer is not going to alter the sound of the rifles cycling action which would go unnoticed when shooting at distance.
On average, suppressors reduce the noise of a gunshot by 20 – 35 decibels (dB), roughly the same sound reduction as earplugs or earmuffs. Maybe Bamber has never shot indoors, so he might think it wise to use the silencer to muffle the sound best he could so not to disturb those sleeping? It doesn’t stop noise all together and probably woukd be less noticeable on the smaller calibre rifle, but why take the risk without using one?
Is a suppressor really worth it?
Less Noise
As was explained above, suppressors bring down the decibels that you hear each and every time a gun is shot. Making less noise while shooting is beneficial if there are a lot of people at the shooting range if you're out hunting, or simply if you're trying to do everything possible to preserve your hearing.