Despite the Relic conversion process being still quite fraught with ceiling-related problems, indeed I found that success rises to 100% by scanning the device from the chamber entrance, awaiting one pulse, then collecting all swiftly! Destroy at most two Scavengers in the corridor, ignore them thereafter, then I found that one dash through the chamber yields one behaving Relic and dislodges the others.
An earlier experiment involved scanning the device from far in the corridor and edging out of sight, which caused the Scavengers not to associate its activation with the interfering Human vehicle in the area, and was quite nice for looking around with Camera suite. From there I noticed that disembarking at all can be enough to free a ceiling Relic, although for me this also caused more problems than it solved—on one occasion the result was a ceiling SRV and a Stuck Recovery, and on another it failed to return SRV control to me after boarding. Driving out and boarding the starship indeed seemed to work.
In any case, is there a known drive to reach Tier 4? It looks plausible given the excess far beyond Tier 3 and the total amount being just shy of six-sevenths, and if so I will try to help with any modest amount more I can create this evening.