Foreign mercenaries volunteering for Ukraine will now be motivated to fight to the death to avoid capture or, much more likely, avoid combat.
Aiden was sworn into the Ukrainian marines in 2018 and is not a “foreign mercenary.” He is a member of the Ukrainian armed forces. I believe that is also the case for the other Englishman as well.
On the other hand, all Russian professional military are considered “contractors” by their army and are treated as such, hence the projection.
Likely avoid capture until they can get out of Ukraine.