How can I stop intruders stealing shuttles and interceptors?
Remove all power from the launch control. This prevents the intruders leaving, although they may still attempt to sabotage ships’ systems or injury your crew. Assign marines to Searching. If Resnig is on-station he will do this, but he may not act quickly or assign enough marines to search. Ideally you should already have some marines on search duty ready to deal with any intruders, particularly if you are operating in hostile space. The location of intruders can be seen on Perscan (ALT+P). You cannot assign marines a specific area to search. Marines will generally kill intruders outright. Badly injured intruders will head towards the Medibay. You can send some marines to the Medibay to deal with the injured intruder.