expl3 - Left pop a list - How to split a temp var coming from a seq_pop_left?

I would like to split a multiline content regarding and then split each item regarding . .

Then I would like to iterate over each list in parallel such as to print their items together suchas to print for example a1i b2ii c3iii.

I am trying to pop from the left the first list to read it item by item but this doesn’t work…
I would like to see a-ok-b-ok-c but I just see a . b . c … An expansion problem I think…

This question is a simplifcation of the real case of use indicated in this post.

documentclass{article}

% Source : https://tex.stackexchange.com/a/475291/6880

RequirePackage{xparse}

ExplSyntaxOn

%seq_new:N l__pmbc_seq % Not useful here.

% #1 : line separator
% #2 : cell separator
% #3 : content
    NewDocumentCommand{splittab}{m m +m}{
        tnscalc_splittab:nnn{#1}{#2}{#3}
    }

% The internal version of the general purpose macro
    cs_new_protected:Nn tnscalc_splittab:nnn{
        % #1 : line separator
        % #2 : cell separator
        % #3 : content

        % A group allows nesting
        group_begin:
            % Split into parts
            seq_set_split:Nnn l__pmbc_seq { #1 } { #3 }

            %int_zero_new:N l_mbc_N_int  % Not useful here.
            %int_set:Nn l_mbc_N_int { seq_count:N l__pmbc_seq }  % Not useful here.
            %
            seq_pop_left:NN l__pmbc_seq {l__temp}
            
            seq_set_split:Nnn l__pmbc_subseq { #2 } { l__temp }
            
            seq_use:Nn l__pmbc_subseq { -ok- }
        group_end:
    } 
ExplSyntaxOff


begin{document}
    splittab{}{.}{ a . b . c  1 . 2 . 3  i . ii . ii }
end{document}

documentclass{article}

% Source : https://tex.stackexchange.com/a/475291/6880

usepackage{xparse}

ExplSyntaxOn

seq_new:N l__tnscalc_splittab_seq
seq_new:N l__tnscalc_subseq_seq
int_new:N l__tnscalc_splittab_int
tl_new:N l__tnscalc_temp_tl

% #1 : line separator
% #2 : cell separator
% #3 : content
NewDocumentCommand{splittab}{m m +m}
 {
  tnscalc_splittab:nnn{#1}{#2}{#3}
 }

% The internal version of the general purpose macro
cs_new_protected:Nn tnscalc_splittab:nnn
 {
  % #1 : line separator
  % #2 : cell separator
  % #3 : content
  % A group allows nesting
  group_begin:
  % Split into parts
  seq_set_split:Nnn l__tnscalc_splittab_seq { #1 } { #3 }

  int_set:Nn l__tnscalc_splittab_int { seq_count:N l__tnscalc_splittab_seq } % why?
  seq_pop_left:NN l__tnscalc_splittab_seq l__tnscalc_temp_tl
  seq_set_split:NnV l__tnscalc_subseq_seq { #2 } l__tnscalc_temp_tl
  seq_use:Nn l__tnscalc_subseq_seq { -ok- }
  group_end:
 } 
ExplSyntaxOff


begin{document}

splittab{}{.}{ a . b . c  1 . 2 . 3  i . ii . ii }

end{document}