Here it would appear that there is a very large supralinear insertion in 𝓞 that involves most, if not all, of the relative clause “that men shall come forth from the dead”. The transcript for 𝓞 in volume 1 of the critical text reads as follows for this passage:
Basically, twice as much text as is possible is supposed to fit within the lacuna, which requires one to supralinearly insert about half of that missing text. One problem with the transcript’s conjectured text for the lacuna is that it seems strange that Oliver Cowdery would have initially written inline the that in “or a third time that it mattereth not”. One possibility, suggested by Don Brugger (personal communication), is that part of the inserted text itself might have been supralinearly inserted above the original supralinear insertion. One example of such multiple supralinearity is found in 𝓞 near the beginning of 2 Nephi:
Another possibility worth considering is that there was no supralinear insertion at all, that the original text lacked the relative clause “that men shall come forth from the dead” (which means that there would have been only some minor crossout in the lacuna). Such a conjecture assumes that when Oliver copied from 𝓞 into 𝓟, he added this long relative clause. One could further propose that Oliver was prompted to make such an addition (set in italics below and listed as 2) by two similar relative clauses, a nearly identical one in verse 4 (listed below as 1) and a somewhat different one at the end of verse 5 (listed below as 3):
The sentence at the beginning of verse 5 would read well enough without the long relative clause: “now whether there shall be one time or a second time or a third time / it mattereth not”. But we have no evidence elsewhere in the text that Oliver ever created in his copywork such a long insertion, either intentionally or accidentally. Despite the difficulty in fitting the entire text within the lacuna, the critical text will accept the earliest extant reading, the one in 𝓟 with the relative clause “that men shall come forth from the dead”.
Summary: Accept in Alma 40:5 the relative clause “that men shall come forth from the dead”, which modifies “one time or a second time or a third time”; it appears that most, if not all, of this long relative clause was supralinearly inserted in what is now a lacuna in 𝓞.