Survivor

[fung_derf]

I believe they had a pre-arranged plan. Malcolm sold him on the idea as working as a team, and if Malcolm was going home, Reynold would thwart their efforts by giving up his idol.
Two benefits I could see. Now, Malcolm has the only idol and no one knows about it. Also, Malcolm can now argue there's no reason to boot off Reynolds as Phillip has been pushing to go after anyone with an idol.
We'll see if Malcolm is a team player (which I doubt) whereas he can at some time in the future return the favor by giving his idol to Reynolds (which would surprise everyone), or he can keep it for himself and use it later. Either way, if Malcolm gets to final three, it will give him an argument as to why he played best.