Can a mixed gas rebreather diver safely dive with a trimix open circuit diver on BSAC branch dives?
Yes. Care should be taken to ensure that decompression schedules and bailout plans are similar to facilitate efficient buddy diving but with good planning it is perfectly possible. Obviously, it is preferable for two mixed gas rebreather divers to dive together using similar diluent mixes and similar decompression tools. In this case the decompression and bailout run time schedules will be similar and dive planning is simplified.