Now this is interesting... very much remembers me of one of RTSL's last contests where the objective was to make a map worth replaying several times... I imagine that should be very much feasible (talking about Source here, never really worked with GoldSrc, as for Source, BMS would present itself as an obvious choice) and would certainly be interesting to play... maybe split the whole thing into three maps (cargo area stealing, cargo area basement kill/help scientist, security station area)?